Graft selection algorithm based on congestion volume for adult living donor liver transplantation

Recurrent Colorectal Liver Metastases in the Liver Remnant After Major Liver Surgery-IRE as a Salvage Local Treatment When Resection and Thermal Ablation are Unsuitable

PURPOSE

To examine the safety and short-term oncologic outcomes of computer-tomography-guided (CT-guided) irreversible electroporation (IRE) of recurrent, irresectable colorectal liver metastases (CRLM) after major hepatectomy deemed unsuitable for thermal ablation.

PATIENTS AND METHODS

Twenty-three patients undergoing CT-guided IRE of recurrent CRLM after major hepatectomy were included in this study. All tumors were located adjacent to sole remaining intrahepatic blood vessels and bile ducts, precluding thermal ablation. Patients underwent systematic clinical and imaging follow-up, including magnetic resonance imaging of the liver at 1-month and 3-month intervals thereafter. Time to local and intrahepatic tumor progression within 12 and 36 months and associated risk factors were assessed using Kaplan Meier and Cox regression analysis, respectively.

RESULTS

Complete ablation with a safety margin of at least 0.5 cm was achieved in 22/23 (95.6%) patients. No vessel injury or thrombosis occurred. Five patients developed moderate biliary stenosis after a median of 4 weeks, without requiring treatment. Local tumor-progression-free rates within 12/36 months were 64%/57.4%, respectively. Intrahepatic-progression-free rate within 12/36 months was 36.4%/19.5%, respectively. Five (23%) patients were tumor-free at the end of follow-up. Multivariate Cox regression analysis did not show any association between local tumor-progression-free rates and patient age, target tumor size, primary tumor side or synchronicity of liver metastases.

CONCLUSION

In this highly selected patient population with local recurrences of CRLM after major surgery, IRE was shown to be a safe salvage treatment option when thermal ablation is unsuitable.

A systematic review of small for size syndrome after major hepatectomy and liver transplantation

BACKGROUND

Major hepatectomy (MH) and particular types of liver transplantation (LT) (reduced size graft, living-donor and split-liver transplantation) lead to a reduction in liver mass. As the portal venous return remains the same it results in a reciprocal and proportionate rise in portal venous pressure potentially resulting in small for size syndrome (SFSS). The aim of this study was to review the incidence, diagnosis and management of SFSS amongst recipients of LT and MH.

METHODS

A systematic review was performed in accordance with the 2010 Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The following terms were used to search PubMed, Embase and Cochrane Library in July 2019: ("major hepatectomy" or "liver resection" or "liver transplantation") AND ("small for size syndrome" or "post hepatectomy liver failure"). The primary outcome was a diagnosis of SFSS.

RESULTS

Twenty-four articles met the inclusion criteria and could be included in this review. In total 2728 patients were included of whom 316 (12%) patients met criteria for SFSS or post hepatectomy liver failure (PHLF). Of these, 31 (10%) fulfilled criteria for PHLF following MH. 8 of these patients developed intractable ascites alongside elevated portal venous pressure following MH indicative of SFSS.

CONCLUSION

SFSS is under-recognised following major hepatectomy and should be considered as an underlying cause of PHLF. Surgical and pharmacological therapies are available to reduce portal congestion and reverse SFSS.

[Navigated liver surgery : Current state and importance in the future]

The preoperative computer-assisted resection planning is the basis for every navigation. Thanks to modern algorithms, the prerequisites have been created to carry out a virtual resection planning and a risk analysis. Thus, individual segment resections can be precisely planned in any conceivable combination. The transfer of planning information and resection suggestions to the operating theater is still problematic. The so-called stereotactic liver navigation supports the exact intraoperative implementation of the planned resection strategy and provides the surgeon with real-time three-dimensional information on resection margins and critical structures during the resection. This is made possible by a surgical navigation system that measures the position of surgical instruments and then presents them together with the preoperative surgical planning data. Although surgical navigation systems have been indispensable in neurosurgery and spinal surgery for many years, these procedures have not yet become established as standard in liver surgery. This is mainly due to the technical challenge of navigating a moving organ. As the liver is constantly moving and deforming during surgery due to respiration and surgical manipulation, the surgical navigation system must be able to measure these alterations in order to adapt the preoperative navigation data to the current situation. Despite these advances, further developments are required until navigated liver resection enters clinical routine; however, it is already clear that laparoscopic liver surgery and robotic surgery will benefit most from navigation technology.

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.

Feasibility of using marginal liver grafts in living donor liver transplantation

Liver transplantation (LT) is one of the most effective treatments for end-stage liver disease caused by related risk factors when liver resection is contraindicated. Additionally, despite the decrease in the prevalence of hepatitis B virus (HBV) over the past two decades, the absolute number of HBsAg-positive people has increased, leading to an increase in HBV-related liver cirrhosis and hepatocellular carcinoma. Consequently, a large demand exists for LT. While the wait time for patients on the donor list is, to some degree, shorter due to the development of living donor liver transplantation (LDLT), there is still a shortage of liver grafts. Furthermore, recipients often suffer from emergent conditions, such as liver dysfunction or even hepatic encephalopathy, which can lead to a limited choice in grafts. To expand the pool of available liver grafts, one option is the use of organs that were previously considered “unusable” by many, which are often labeled “marginal” organs. Many previous studies have reported on the possibilities of using marginal grafts in orthotopic LT; however, there is still a lack of discussion on this topic, especially regarding the feasibility of using marginal grafts in LDLT. Therefore, the present review aimed to summarize the feasibility of using marginal liver grafts for LDLT and discuss the possibility of expanding the application of these grafts.

Small for size syndrome difficult dilemma: Lessons from 10 years single centre experience in living donor liver transplantation

AIM

To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome (SFSS) after living donor liver transplantation (LDLT).

METHODS

Through-out more than 10 years: During the period from April 2003 to the end of 2013, 174 adult-to-adults LDLT (A-ALDLT) had been performed at National Liver Institute, Menoufiya University, Shibin Elkoom, Egypt. We collected the data of those patients to do this cohort study that is a single-institution retrospective analysis of a prospectively collected database analyzing the incidence, risk factors, prevention, treatment and outcome of SFSS in a period started from the end of 2013 to the end of 2015. The median period of follow-up reached 40.50 m, range (0-144 m).

RESULTS

SFSS was diagnosed in 20 (11.5%) of our recipients. While extra-small graft [small for size graft (SFSG)], portal hypertension, steatosis and left lobe graft were significant predictors of SFSS in univariate analysis (P = 0.00, 0.04, 0.03, and 0.00 respectively); graft size was the only independent predictor of SFSS on multivariate analysis (P = 0.03). On the other hand, there was lower incidence of SFSS in patients with SFSG who underwent splenectomy [4/10 (40%) SFSS vs 3/7 (42.9%) no SFSS] but without statistical significance, However, there was none significant lower incidence of the syndrome in patients with right lobe (RL) graft when drainage of the right anterior and/or posterior liver sectors by middle hepatic vein, V5, V8, and/or right inferior vein was done [4/10 (28.6%) SFSS vs 52/152 (34.2%) no SFSS]. The 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients with SFSS were 30%, 30%, 25%, 25%, 25% and 25% respectively, while, the 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients without SFSS were 70.1%, 65.6%, 61.7%, 61%, 59.7%, and 59.7% respectively, with statistical significant difference (P = 0.00).

CONCLUSION

SFSG is the independent and main factor for occurrence of SFSS after A-ALDLT leading to poor outcome. However, the management of this catastrophe depends upon its prevention (i.e., selecting graft with proper size, splenectomy to decrease portal venous inflow, and improving hepatic vein outflow by reconstructing large draining veins of the graft).

Small for size syndrome difficult dilemma: Lessons from 10 years single centre experience in living donor liver transplantation

AIM

To analyze the incidence, risk factors, prevention, treatment and outcome of small for size syndrome (SFSS) after living donor liver transplantation (LDLT).

METHODS

Through-out more than 10 years: During the period from April 2003 to the end of 2013, 174 adult-to-adults LDLT (A-ALDLT) had been performed at National Liver Institute, Menoufiya University, Shibin Elkoom, Egypt. We collected the data of those patients to do this cohort study that is a single-institution retrospective analysis of a prospectively collected database analyzing the incidence, risk factors, prevention, treatment and outcome of SFSS in a period started from the end of 2013 to the end of 2015. The median period of follow-up reached 40.50 m, range (0-144 m).

RESULTS

SFSS was diagnosed in 20 (11.5%) of our recipients. While extra-small graft [small for size graft (SFSG)], portal hypertension, steatosis and left lobe graft were significant predictors of SFSS in univariate analysis (P = 0.00, 0.04, 0.03, and 0.00 respectively); graft size was the only independent predictor of SFSS on multivariate analysis (P = 0.03). On the other hand, there was lower incidence of SFSS in patients with SFSG who underwent splenectomy [4/10 (40%) SFSS vs 3/7 (42.9%) no SFSS] but without statistical significance, However, there was none significant lower incidence of the syndrome in patients with right lobe (RL) graft when drainage of the right anterior and/or posterior liver sectors by middle hepatic vein, V5, V8, and/or right inferior vein was done [4/10 (28.6%) SFSS vs 52/152 (34.2%) no SFSS]. The 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients with SFSS were 30%, 30%, 25%, 25%, 25% and 25% respectively, while, the 6-mo, 1-, 3-, 5-, 7- and 10-year survival in patients without SFSS were 70.1%, 65.6%, 61.7%, 61%, 59.7%, and 59.7% respectively, with statistical significant difference (P = 0.00).

CONCLUSION

SFSG is the independent and main factor for occurrence of SFSS after A-ALDLT leading to poor outcome. However, the management of this catastrophe depends upon its prevention (i.e., selecting graft with proper size, splenectomy to decrease portal venous inflow, and improving hepatic vein outflow by reconstructing large draining veins of the graft).

Graft inflow modulation in adult-to-adult living donor liver transplantation: A systematic review

INTRODUCTION

Small-for-size syndrome (SFSS) has an incidence between 0 and 43% in small-for-size graft (SFSG) adult living donor liver transplantation (LDLT). Portal hypertension following reperfusion and the hyperdynamic splanchnic state are reported as the major triggering factors of SFSS. Intra- and postoperative strategies to prevent or to reduce its onset are still under debate. We analyzed graft inflow modulation (GIM) during adult LDLT considering the indications, efficacy of the available techniques, changes in hemodynamics and outcomes.

MATERIALS AND METHODS

A systematic literature search was performed using PubMed, EMBASE, Scopus and the Cochrane Library Central. Treatment outcomes including in-hospital mortality and morbidity, re-transplantation rate, 1-, 3-, and 5-year patient overall survival and 1-, 3-, and 5-year graft survival rates, hepatic artery and portal vein flows and pressures before and after inflow modulation were analyzed.

RESULTS

From 563 articles, 12 studies dated between 2003 and 2014 fulfilled the selection criteria and were therefore included in the study. These comprised a total of 449 adult patients who underwent inflow modulation during adult-to-adult LDLT. Types of GIM described were splenic artery ligation, splenectomy, meso-caval shunt, spleno-renal shunt, portocaval shunt, and splenic artery embolization. Mortality and morbidity ranged between 0 and 33% and 17% and 70%, respectively. Re-transplantation rates ranged between 0% and 25%. GIM was associated with good survival for both graft and recipients, reaching an 84% actuarial rate at 5 years. Through the use of GIM, irrespective of the technique, a statistically significant reduction of PVF and PVP was obtained.

CONCLUSIONS

GIM is a safe and efficient technique to avoid or limit portal hyperperfusion, especially in cases of SFSG, decreasing overall morbidity and improving outcomes.

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.

Segment 4 and the left lateral segment regeneration pattern after resection of the middle hepatic vein in a living donor right hepatectomy

BACKGROUND

Inclusion of the middle hepatic vein (MHV) with a right hepatectomy (RH) in live donor liver transplantation improves venous drainage of the anterior sector of the graft. Its long-term effects on donor left liver (LL) regeneration are not well described.

METHODS

Donors who underwent RH with MHV (MHV+, n = 12) were compared with donors who underwent RH with preservation of the MHV (MHV-, n = 24). Peri-operative complications and volume of the entire liver and individual segments were evaluated at 1 year post-donation.

RESULTS

There was a trend towards a higher complication rate in the MHV+ group (41% versus 25%), without reaching statistical significance (P = 0.3). Males, high body mass index (BMI) and a smaller residual liver volume (RLV) were predictors for greater LL regeneration. MHV+ donors had impaired regeneration of segment 4 (S4) at 1 year, and compensatory greater left lateral segment regeneration. The absence of venous drainage of S4 (V4) to left hepatic vein (LHV) was a predictor of impaired S4 regeneration.

CONCLUSIONS

Regeneration of S4 is impaired in MHV+ donors. Caution should be taken when considering MHV removal on donors with dominant S4, especially on those with potential increased demand for liver regeneration, such as males, higher BMI and a smaller RLV.

[Specific considerations in living-donor liver transplantation]

INTRODUCTION

Due to the limited number of cadaver donors, adult living liver donor transplantation became an alternative for liver transplantation. During living liver donor transplantation, the safety and uncomplicated recovery of the donor are as important as the appropriate volume and weight of the donated graft. The middle hepatic vein causes a significant dilemma, due to the special anatomical position. The reconstruction of the middle hepatic vein branches supplying S5, S8 is suggested when the anatomically right liver lobe is transplanted.

AIM

The aim of the present study was to investigate the requirements of the reconstruction of middle hepatic vein and to give an accurate description about the discrepancy between the portal vein in- and outflow.

METHOD

The authors analyzed the liver anatomic characteristics of 130 donors undergoing living liver donor transplantation with the use of MeVis software. The so-called porto-hepatic disparity index (shift) was introduced.

RESULTS

The right hepatic vein was dominant in 64.6% of all cases, while the left hepatic vein was never observed to be dominant. The territories of V5 and V8 were responsible for the 33.2±8.9% of the right hepatic lobe area. The correlation between portal venous territory and vein dominancy were as follows: R2 = 0.7811 in the left liver lobe; R² = 0.5463 in the area of middle hepatic vein and R² = 0.5843 in the case of the right hepatic vein. The average value of the shift was 28.2%.

CONCLUSIONS

The differences among the pattern of portal in- and hepatic outflow is an important issue that should be taken into consideration when deciding the necessity for reconstruction of the middle hepatic vein.

Sequential preoperative hepatic vein embolization after portal vein embolization for extended left hepatectomy in colorectal liver metastases

Background

The role of portal vein embolization to increase future liver remnant (FLR) is well-established in the treatment of colorectal liver metastases. However, the role of hepatic vein embolization is unclear.

Case report

A patient with colorectal liver metastases received neoadjuvant chemotherapy prior to attempted resection. At the time of resection his tumor appeared to invade the left and middle hepatic vein, requiring an extended left hepatectomy including segments five and eight. Post-operatively, he underwent sequential left portal vein embolization followed by left hepatic vein embolization and finally, middle hepatic vein embolization. Hepatic vein embolization was performed to increase the FLR as well as to allow collateral drainage of the FLR to develop. A left trisectionectomy was then performed and no evidence of postoperative liver congestion or morbidity was found.

Conclusion

Sequential portal vein embolization and hepatic vein embolization for extended left hepatectomy may be considered to increase FLR and may prevent right hepatic congestion after sacrificing the middle vein.

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.

Small-for-size syndrome in living donor liver transplantation

When the graft volume is too small to satisfy the recipient's metabolic demand, the recipient may thus experience small-for-size syndrome (SFSS). Because the occurrence of SFSS is determined by not only the liver graft volume but also a combination of multiple negative factors, the definitions of small-for-size graft (SFSG) and SFSS are different in each institute and at each time. In the clinical setting, surgical inflow modulation and maximizing the graft outflow are keys to overcoming SFSS. Accordingly, relatively smaller-sized grafts can be used with surgical modification and pharmacological manipulation targeting portal circulation and liver graft quality. Therefore, the focus of the SFSG issue is now shifting from how to obtain a larger graft from the living donor to how to manage the use of a smaller graft to save the recipient, considering donor safety to be a priority.

The "carving" liver partitioning technique for graft hepatectomy in live donor liver transplantation: a single-center experience

BACKGROUND

In adult live donor liver transplantation, postoperative venous congestion of graft and remnant livers can lead to life-threatening complications. The purpose of this study was to evaluate the safety and benefits of our 3-dimensional, computed tomographic, computer-assisted donor hepatectomy using the "carving" partitioning technique.

METHODS

Eighty-three consecutive adult live donor liver transplantations were performed based on data obtained from individualized preoperative 3-dimensional, computed tomographic reconstructions and virtual graft hepatectomies.

RESULTS

There were 71 right and 12 left grafts. Small grafts (graft volume body weight ratio, <1.0) were used in 20 cases. We observed no clinically important differences in postoperative function between right and left grafts. Four recipients developed lethal small-for-size syndrome. Reversible small-for-size syndrome was observed in a right graft recipient and in 2 right graft donors.

CONCLUSION

Preoperative 3-dimensional, computed tomographic, computer-assisted planning using virtual liver partitioning allowed for: (1) an individualized carving technique based on specific donor anatomic characteristics, (2) donor safety based on individualized patterns of venous outflow, and (3) optimized drainage of the medial area of the graft based on the preferential inclusion of the middle hepatic vein.

Effect of portal haemodynamics on liver graft and intestinal mucosa after small-for-size liver transplantation in swine

BACKGROUND

After small-for-size graft (SFSG) transplantation, elevated portal venous pressure (PVP) may lead to postoperative liver damage. Herein we evaluated the impact of portocaval shunt (PCS) to control PVP on liver grafts and intestine following SFSG transplantation.

METHODS

Nineteen SFSG transplantations were performed with 30% of native liver in swine. Swine were divided into 3 groups: a high-flow shunt group (HS: n = 7), in which portal venous flow (PVF) was reduced with a 10-mm diameter PCS; a low-flow shunt group (LS: n = 6), in which PVF was reduced with a 5-mm diameter PCS, and a no-shunt group (NS: n = 6), in which no PCS was placed.

RESULTS

Seven-day survivals were 83.3% in NS, 100% in LS and 0% in HS (p = 0.0088). PVP was significantly higher in the NS group (p = 0.0001; mean ± SEM NS/LS/HS: 20.5 ± 0.7/14.0 ± 1.2/11.6 ± 0.5 mm Hg). The LS group exhibited the highest compliance (PVF/PVP; NS/LS/HS 42.7 ± 10.9/44.6 ± 4.9/37.7 ± 8.3 ml/min/mm Hg; p = 0.009), the lowest aspartate aminotransferase (NS/LS/HS 562 ± 18/370 ± 55/720 ± 130 IU/l; p = 0.0493), and suppressed deleterious alternations of the hepatic parenchyma and intestinal mucosa.

CONCLUSIONS

Portal hypertension after SFSG transplantation impaired liver and intestinal mucosa; however, inadequate portal flow impaired not only the liver, but also survival.

Clinical anatomy related to the hepatic veins for right lobe living donor liver transplantation

The complexity of liver reconstruction has limited partial right lobe living donor liver transplantation. It is largely due to the difficulty of dealing with the middle hepatic vein. We sought to define the anatomic features of hepatic veins. Forty-one fresh adult livers, 43 formalin-fixed adult cadaver livers, and 91 adult liver corrosion casts were used for the study. We determined the number of branches, the maximum diameter, the whole length, the extrahepatic length of the hepatic veins, and the deviation of the middle hepatic vein from the main portal fissure. Nakamura and Tsuzuki's classification of hepatic vein types was used. Type A, B, and C accounted for 59.4, 27.8, and 12.8% of all specimens in this study, respectively. The middle and left hepatic veins formed a common trunk in 60.3% of the specimens, and the length of the common trunk was 1.12 ± 0.62 cm. The degree of deviation to the right of the middle hepatic vein from the main portal fissure was 14.11° ± 12.65°. The frequency of hepatic vein types and the degree of deviation to the right of the middle hepatic vein in this study is markedly different from that reported in other literature. The anatomic features of the hepatic veins in this study suggest that right lobe living donor liver transplantation is more suitable for Chinese.

Left-sided grafts for living-donor liver transplantation and split grafts for deceased-donor liver transplantation: their impact on long-term survival

BACKGROUND

A small-for-size graft is important in living-donor liver transplantation (LDLT) and deceased-donor liver transplantation (DDLT).

SUBJECTS AND METHODS

First, we confirmed the effect of initial graft volume on survival using a rat model of liver transplantation (LT). We then evaluated the actual long-term survival based on graft type in 1421 LTs (including 1364 LDLTs) at Kyoto University and 2000 DDLTs at the Mayo Clinic, to evaluate donor safety in LDLT and the possibility of shifting to split orthotopic liver transplantation (SOLT) in DDLT.

RESULTS

In the rat model, SOLTs with 40%- and 20%-grafts had a poor survival. A total of 697 pediatric LTs showed good long-term outcomes (survival rate was 0.764 at 21.2 years). The survival rate of 724 adult LTs was 0.664 at 17.8 years. The survival rates of auxiliary partial orthotopic liver transplantation with a left-sided graft (0.421 at 15.0 years) and SOLT with a left-sided graft (0.000 at 0.8 years) need to be improved. Although the survival rate of 1965 adult DDLTs with a whole-liver graft in the Mayo Clinic was 0.727 at 12.8 years, that of adult SOLT was 0.595 at 11.0 years.

CONCLUSION

From the viewpoint of greater donor safety and expanded donor candidates in LDLT, the choice of a left-sided graft still remains controversial. A shift to SOLT to achieve excellent results should be established to resolve a donor shortage in DDLT.

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.

Evaluation of standard liver volume formulae for Chinese adults

AIM: To evaluate different standard liver volume (SLV) formula and verify the applicability of the formulae for Chinese adults.

METHODS: Data from 70 cases of living donor liver transplantation (LDLT) performed at our transplantation centers between January 2008 and April 2009 were analyzed. SLV was estimated using our recently reported formula [the Chengdu formula: SLV (mL) = 11.5 × body weight (kg) + 334] and other reported formulae used for Chinese adults. Actual intraoperative liver volumes were obtained from a review of the patients’ medical records.

RESULTS: The actual right liver volume was not significantly different from the estimated right liver volume determined by the Chengdu formula, but was significantly smaller than estimates using the Heinemann, Urata, Vauthey, and Lee formulae (P < 0.01), and significantly larger than estimates using the Fan formula (P < 0.05).

CONCLUSION: The Chengdu formula was demonstrated to be reliable by its application in LDLT.

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.

Current concept of small-for-size grafts in living donor liver transplantation

The extended application of living donor liver transplantation (LDLT) has revealed the problem of graft size mismatching called "small-for-size (SFS) graft syndrome." The initial trials to resolve this problem involved increasing the procured graft size, from left to right, and even extension to include a right lobe graft. Clinical cases of living right lobe donations have been reported since then, drawing attention to the risks of increasing the liver volume procured from a living donor. However, not only other modes of increasing graft volume such as auxiliary or dual liver transplantation, but also control of the increased portal pressure caused by an SFS graft, such as a portosystemic shunt or splenectomy, have been trialed with some positive results. To establish an effective strategy for transplanting SFS grafts and preventing SFS graft syndrome, it is essential to have precise knowledge and tactics to evaluate graft quality and graft volume, when performing these LDLTs with portal pressure control. We reviewed the updated literature on the pathogenesis of and strategies for using SFS grafts.

Portal vein segmentation of a 3D-planning system for liver surgery--in vivo evaluation in a porcine model

BACKGROUND

Computer systems allow the planning of complex liver operations. The segmentation of intrahepatic vessels builds the basis for the calculation of liver segments and resection proposals. For surgical use, it is essential to know the capabilities and limitations of the segmentation. The aim of this study was to determine the sensitivity and precision of the portal vein segmentation of a computer planning system for liver surgery in vivo.

METHODS

Segmentations were performed with the software system HepaVision on computed tomography (CT) scan data of domestic pigs. An in situ corrosion cast of the portal vein served as the gold standard. The segmentation results of the portal vein and the corrosion cast were compared with regard to sensitivity, precision, and amount of short-circuit segmentations.

RESULTS

The methodology demonstrated high resolution ex situ. The in vivo sensitivity of the portal vein segmentation was 100% for vessels of more than 5 mm in diameter and 82% for vessels of 3-4 mm. All segment branches were detected as well as 84% of the first subsegment branches with a diameter of more than 3 mm. The precision of the system was 100% for segment branches and 89% for the first subsegment vessels. The amount of internal short-circuit segmentations was less than 3.0%. No external short-circuits were found.

CONCLUSION

The system has a high precision and sensitivity under clinical conditions. The segmentation is suitable for portal vein branches of the first and second order and for vessels of >/=3 mm in diameter.