Hepatic venous outflow reconstruction in right lobe graft without middle hepatic vein

Prediction and management of small-for-size syndrome in living donor liver transplantation

Small-for-size syndrome (SFSS) remains a critical challenge in living donor liver transplantation (LDLT), characterized by graft insufficiency due to inadequate liver volume, leading to significant postoperative morbidity and mortality. As the global adoption of LDLT increases, the ability to predict and manage SFSS has become paramount in optimizing recipient outcomes. This review provides a comprehensive examination of the pathophysiology, risk factors, and strategies for managing SFSS across the pre-, intra-, and postoperative phases. The pathophysiology of SFSS has evolved from being solely volume-based to incorporating portal hemodynamics, now recognized as small-for-flow syndrome. Key risk factors include donor-related parameters like age and graft volume, recipient-related factors such as MELD score and portal hypertension, and intraoperative factors related to venous outflow and portal inflow modulation. Current strategies to mitigate SFSS include careful graft selection based on graft-to-recipient weight ratio and liver volumetry, surgical techniques to optimize portal hemodynamics, and novel interventions such as splenic artery ligation and hemiportocaval shunts. Pharmacological agents like somatostatin and terlipressin have also shown promise in modulating portal pressure. Advances in 3D imaging and artificial intelligence-based volumetry further aid in preoperative planning. This review emphasizes the importance of a multifaceted approach to prevent and manage SFSS, advocating for standardized definitions and grading systems. Through an integrated approach to surgical techniques, hemodynamic monitoring, and perioperative management, significant strides can be made in improving the outcomes of LDLT recipients. Further research is necessary to refine these strategies and expand the application of LDLT, especially in challenging cases involving small-for-size grafts.

Preventing Small-for-size Syndrome in Living Donor Liver Transplantation: Guidelines From the ILTS-iLDLT-LTSI Consensus Conference

Small-for-size syndrome (SFSS) is a well-recognized complication following liver transplantation (LT), with up to 20% developing this following living donor LT (LDLT). Preventing SFSS involves consideration of factors before the surgical procedure, including donor and recipient selection, and factors during the surgical procedure, including adequate outflow reconstruction, graft portal inflow modulation, and management of portosystemic shunts. International Liver Transplantation Society, International Living Donor Liver Transplantation Group, and Liver Transplant Society of India Consensus Conference was convened in January 2023 to develop recommendations for the prediction and management of SFSS in LDLT. The format of the conference was based on the Grading of Recommendations, Assessment, Development, and Evaluation system. International experts in this field were allocated to 4 working groups (diagnosis, prevention, anesthesia, and critical care considerations, and management of established SFSS). The working groups prepared evidence-based recommendations to answer-specific questions considering the currently available literature. The working group members, independent panel, and conference attendees served as jury to edit and confirm the final recommendations presented at the end of the conference by each working group separately. This report presents the final statements and evidence-based recommendations provided by working group 2 that can be implemented to prevent SFSS in LDLT patients.

Small-For-Size Syndrome and Graft Inflow Modulation Techniques in Liver Transplantation

BACKGROUND

Partial liver transplantation has recently been proposed to alleviate organ shortages. However, transplantation of a small-for-size graft is associated with an increased risk of posttransplant hepatic dysfunction, commonly referred to as small-for-size syndrome (SFSS). This review describes the etiology, pathological features, clinical manifestations, and diagnostic criteria of SFSS. Moreover, we summarize strategies to improve graft function, focusing on graft inflow modulation techniques. Finally, unmet needs and future perspectives are discussed.

SUMMARY

In fact, posttransplant SFSS can be attributed to various factors such as preoperative status of the recipients, surgical techniques, donor age, and graft quality, except for graft size. With targeted improvement measures, satisfactory clinical outcomes can be achieved in recipients at increased risk of SFSS. Given the critical role of relative portal hyperperfusion in the pathogenesis of SFSS, various pharmacological and surgical treatments have been established to reduce or partially divert excessive portal inflow, and recipients will benefit from individualized therapeutic regimens after careful evaluation of benefits against potential risks. However, there remain unmet needs for further research into different aspects of SFSS to better understand the correlation between portal hemodynamics and patient outcomes.

KEY MESSAGES

Contemporary transplant surgeons should consider various donor and recipient factors and develop case-specific prevention and treatment strategies to improve graft and recipient survival rates.

Small-for-size syndrome in liver transplantation: Definition, pathophysiology and management

BACKGROUND

Since the first success in an adult patient, living donor liver transplantation (LDLT) has become an universally used procedure. Small-for-size syndrome (SFSS) is a well-known complication after partial LT, especially in cases of adult-to-adult LDLT. The definition of SFSS slightly varies among transplant physicians. The use of a partial liver graft has risks of SFSS development. Persistent portal vein (PV) hypertension and PV hyper-perfusion after LT were identified as the main factors. Hence, various approaches were explored to modulate PV flow and decrease PV pressure in order to alleviate this syndrome. Herein, the definition, clinical symptoms, pathophysiology, basic research, as well as preventive and treatment strategies for SFSS are reviewed based on an extensive review of the literature and on our own experiences.

DATA SOURCES

The articles were collected through PubMed using search terms "liver transplantation", "living donor liver transplantation", "living liver donation", "partial graft", "small-for-size graft", "small-for-size syndrome", "graft volume", "remnant liver", "standard liver volume", "graft to recipient body weight ratio", "sarcopenia", "porcine", "swine", and "rat". English publications published before March 31, 2020 were included in this review.

RESULTS

Many transplant surgeons performed PV flow modulation, including portocaval shunt, splenic artery ligation and splenectomy. With these techniques, patient outcome has been improved even when using a "small" graft. Other factors, such as preoperative recipients' nutritional and skeletal muscle status, graft congestion, and donor factors, were also identified as risk factors which all have been addressed using various strategies.

CONCLUSIONS

The surgical approach controlling PV flow and pressure could help to prevent SFSS especially in severely ill recipients. In the absence of efficacious medications to resolve SFSS, conservative treatments, including aggressive fluid balance correction for massive ascites, anti-microbiological therapy to prevent or control sepsis and intensive nutritional therapy, are all required if SFSS could not be prevented.

In situ reconstruction of vascular inflow/outflow to left lateral liver section, ex-vivo liver resection and autologous liver transplantation of remaining liver remnant for hepatic alveolar echinococcosis

OBJECTIVE

This is a case report on a patient with advanced hepatic alveolar echinococcosis (HAE) treated with autologous liver transplantation without any veno-venous bypass using the modified technique of ex vivo liver resection and autologous liver transplantation (the ERAT technique).

METHOD

A 27-year old male with advanced HAE underwent in situ reconstruction of vascular inflow/outflow to left lateral liver section, ex-vivo liver resection and autologous liver transplantation of remaining liver remnant (the modified ERAT technique). The operation consisted of hepatotomy along the right border of the falciform ligament, reconstruction of portal vein supplying the left lateral liver section, reconstruction of left hepatic vein, followed by removal of liver segments S1, S4 to S8, ex vivo resection of all involved tissues within these liver segments in the liver remnant, and autologous liver transplantation of the resected liver remnant. The whole surgical procedure lasted for 12 h, and the blood lost was 800 mL. The patient recovered uneventfully in the post-operation period.

CONCLUSION

The in situ reconstruction of the vascular inflow/outflow of left lateral liver section maintained the PV circulation and provided liver functional support during the operation. The subsequent autologous liver transplantation provided additional liver functional tissues, thus reduced the risk of post-hepatectomy liver failure. This surgical procedure did not require any veno-venous bypass.

Comparison of Patients With and Without Anterior Sector Venous Drainage in Right Lobe Liver Transplantation From Live Donors in Terms of Complications, Rejections, and Graft Survival: Single-Center Experience

AIM

The issue of performing an anastomosis of the anterior sector veins to the vena cava in living donor liver transplantation is still controversial. We aimed to research whether there was any difference in terms of complications, rejections, and graft survival between patients with and without anterior sector venous drainage to the vena cava.

PATIENTS AND METHODS

Patients were retrospectively investigated for demographic data and ratio of graft needed to available graft weight. Donors had volumetric calculations and middle hepatic vein anterior sector drainage documented in detail.

RESULTS

Seventy-three donors with middle hepatic vein drainage were included. Thirty-five had anterior sector venous drainage performed and 38 patients did not have drainage procedures performed. The incidence of general complications was higher in the group without anterior sector drainage (78.3% and P = .002). Biloma linked to bile leaks were observed in 8 patients without drainage (72.8%) and 3 patients with drainage (27.2%). Late acute rejection occurring during follow up after transplantation was identified in 28 patients (11.6%). Of these, 1 (14.3%) had anterior sector drainage and 6 (85.7%) were in the patient group without drainage (P = .067).

CONCLUSION

As a result of this study, for patients with grafts at the volume limit (graft weight to receiver weight ratio <0.8) and with congestion observed in the anterior sector after liver implantation and for patients with outflow problems identified on Doppler ultrasonography, anterior sector veins >5 mm should definitely be drained into the vena cava. Hence, both complication and rejection rates will reduce, and we can lengthen the graft, and thus patient, survival.

Novel techniques and preliminary results of ex vivo liver resection and autotransplantation for end-stage hepatic alveolar echinococcosis: A study of 31 cases

Ex vivo liver resection combined with autotransplantation is a recently introduced approach to cure end-stage hepatic alveolar echinococcosis (HAE), which is considered unresectable by conventional radical resection due to echinococcal dissemination into the crucial intrahepatic conduits and adjacent structures. This article aims discuss the manipulation details and propose reasonable indications for this promising technique. All patients successfully underwent liver autotransplantation with no intraoperative mortality. The median weight of the autografts was 636 g (360-1300 g), the median operation time was 12.5 hours (9.4-19.5 hours), and the median anhepatic phase was 309 minutes (180- 460 minutes). Intraoperative blood loss averaged 1800 mL (1200-6000 mL). Postoperative complications occurred in 13 patients during hospitalization; 5 patients experienced postoperative complications classified as Clavien-Dindo grade III or higher, and 2 patients died of intraabdominal bleeding and acute cerebral hemorrhage, respectively. Twenty-nine patients were followed for a median of 14.0 months (3-42 months), and no HAE recurrence was detected. The technique requires neither an organ donor nor any postoperative immunosuppressant, and the success of the treatment relies on meticulous preoperative assessments and precise surgical manipulation.

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.

Liver autotransplantation and retrohepatic vena cava reconstruction for alveolar echinococcosis

BACKGROUND

Alveolar echinococcosis (AE) is characterized by a slow-growing infiltrative neoplasm that is often unresectable by traditional methods because of strong adhesions and invasion to adjacent structures. We present our experience with liver autotransplantation and retrohepatic inferior vena cava (RHIVC) reconstruction using autogenous veins in patients with this end-stage parasitic disease.

METHODS

Twelve patients with hepatic AE and extensive RHIVC, hepatic vein, and/or hilar invasion underwent ex vivo liver resection and RHIVC reconstruction using autogenous veins followed by autotransplantation in the West China Hospital of Sichuan University from 2013 to 2016.

RESULTS

The mean weight of the harvested liver graft was 537 g (range: 390-900 g), the mean anhepatic time was 216 min (range, 120-310 min), and the mean operation time was 13.6 h (range, 10.5-19.5 h). The main postoperative complication was bile leakage. The mean postoperative hospital stay was 16.4 d (range, 10.0-37.0 d), and the median follow-up time was 15.5 mo (range, 1.0-32.0 mo). All patients were alive at the latest follow-up. The vascular patency rate was 100%, and no residual disease, recurrence, or metastasis was detected.

CONCLUSIONS

To our knowledge, liver autotransplantation and RHIVC reconstruction using autogenous veins are rarely performed for patients with end-stage hepatic AE. This technique requires no organ donor, allogeneic, or artificial vessel implantation, postoperative immunosuppressive therapy, or long-term postoperative anticoagulant treatment. These benefits may make the treatment of select end-stage hepatic AE patients more affordable and effective.

Reconstructing middle hepatic vein tributaries in right-lobe living donor liver transplantation

AIMS

To investigate the effectiveness of our technique and policy in reconstructing middle hepatic vein (MHV) tributaries of patients undergoing right-lobe living donor liver transplantation (LDLT).

METHODS

From January 2001 to December 2010, 186 adult patients underwent right-lobe LDLT without the MHV. Patients were divided into two groups: group A (n = 71) and group B (n = 115) without or with the MHV tributaries reconstruction. We evaluated the serum liver function markers after transplantation and monitored vascular flow in the graft and interpositional vein by Doppler ultrasonography.

RESULTS

The cumulative 1-, 3-, 5-year graft and patient survival rates were not significant between group A and group B (p = 0.287 and p = 0.258). Biliary complications appeared to be more frequent in group A than in group B (16.9 vs. 5.2%, p = 0.009). Liver function impairment was found in patients without MHV reconstruction and those with occluded interpositional vessels early after transplantation. The cumulative 1-, 3-, 6- and 12-month patency rate of the interpositional veins was 81.51, 79.60, 74.69 and 72.68%, respectively.

CONCLUSION

The reconstruction technique based on our policy ensures excellent outflow drainage and favorable recipient outcome, while better criteria for MHV reconstruction should be established.

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.

Donor safety and remnant liver volume in living donor liver transplantation

AIM: To evaluate the relationship between donor safety and remnant liver volume in right lobe living donor liver transplantation (LDLT).

METHODS: From July 2001 to January 2009, our liver transplant centers carried out 197 LDLTs. The clinical data from 151 cases of adult right lobe living donors (not including the middle hepatic vein) were analyzed. The conditions of the three groups of donors were well matched in terms of the studied parameters. The donors’ preoperative data, intraoperative and postoperative data were calculated for the three groups: Group 1 remnant liver volume (RLV) < 35%, group 2 RLV 36%-40%, and group 3 RLV > 40%. Comparisons included the different remnant liver volumes on postoperative liver function recovery and the impact of systemic conditions. Correlations between remnant liver volume and post-operative complications were also analyzed.

RESULTS: The donors’ anthroposomatology data, operation time, and preoperative donor blood test indicators were calculated for the three groups. No significant differences were observed between the donors’ gender, age, height, weight, and operation time. According to the Chengdu standard liver volume formula, the total liver volume of group 1 was 1072.88 ± 131.06 mL, group 2 was 1043.84 ± 97.11 mL, and group 3 was 1065.33 ± 136.02 mL. The three groups showed no statistically significant differences. When the volume of the remnant liver was less than 35% of the total liver volume, the volume of the remnant had a significant effect on the recovery of liver function and intensive care unit time. In addition, the occurrence of complications was closely related to the remnant liver volume. When the volume of the remnant liver was more than 35% of the total liver volume, the remnant volume change had no significant effect on donor recovery.

CONCLUSION: To ensure donor safety, the remnant liver volume should be greater than the standard liver volume (35%) in right lobe living donor liver transplantation.

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.

Management of venous stenosis in living donor liver transplant recipients

AIM: To retrospectively evaluate the management and outcome of venous obstruction after living donor liver transplantation (LDLT).

METHODS: From February 1999 to May 2009, 1 intraoperative hepatic vein (HV) tension induced HV obstruction and 5 postoperative HV anastomotic stenosis occurred in 6 adult male LDLT recipients. Postoperative portal vein (PV) anastomotic stenosis occurred in 1 pediatric left lobe LDLT. Patients ranged in age from 9 to 56 years (median, 44 years). An air balloon was used to correct the intraoperative HV tension. Emergent surgical reoperation, transjugular HV balloon dilatation with stent placement and transfemoral venous HV balloon dilatation was performed for HV stenosis on days 3, 15, 50, 55, and 270 after LDLT, respectively. Balloon dilatation followed with stent placement via superior mesenteric vein was performed for the pediatric PV stenosis 168 d after LDLT.

RESULTS: The intraoperative HV tension was corrected with an air balloon. The recipient who underwent emergent reoperation for hepatic stenosis died of hemorrhagic shock and renal failure 2 d later. HV balloon dilatation via the transjugular and transfemoral venous approach was technically successful in all patients. The patient with early-onset HV stenosis receiving transjugular balloon dilatation and stent placement on the 15th postoperative day left hospital 1 wk later and disappeared, while the patient receiving the same interventional procedures on the 50th postoperative day died of graft failure and renal failure 2 wk later. Two patients with late-onset HV stenosis receiving balloon dilatation have survived for 8 and 4 mo without recurrent stenosis and ascites, respectively. Balloon dilatation and stent placement via the superior mesenteric venous approach was technically successful in the pediatric left lobe LDLT, and this patient has survived for 9 mo without recurrent PV stenosis and ascites.

CONCLUSION: Intraoperative balloon placement, emergent reoperation, proper interventional balloon dilatation and stent placement can be effective as a way to manage hepatic and PV stenosis during and after LDLT.

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.

A simple formula to calculate the liver drainage volume of the accessory right hepatic vein using its diameter alone

BACKGROUND

The liver sometimes has an accessory middle or inferior right hepatic vein (RHV) in addition to the usually existing superior RHV. In liver surgery, it is important to know the parenchymal drainage volume of these accessory RHVs to avoid postoperative liver dysfunction caused by blood congestion. The purpose of this study was to determine methods to estimate parenchymal drainage volume of such accessory veins.

METHODS

By reviewing the preoperative multidetector-row computed tomography (MDCT) and using specialist software, we investigated the presence of accessory RHVs, the diameter, and the parenchymal drainage volume of each vein, and we determined correlations between the diameter and parenchymal drainage volume of the accessory RHVs.

RESULTS

Middle (median diameter, 4.9 mm) and inferior (median diameter, 5.0 mm) RHVs were present in 15% and 47%, respectively, in this study. The median parenchymal drainage volume of the superior, middle, and inferior RHVs was 401 mL, 64 mL, and 116 mL, respectively. There were positive correlations between diameters and the parenchymal drainage volume of accessory RHVs (middle RHV: y = 27.1x-45.7, r = .78, P < .05; inferior RHV: y = 34.8x-57.8, r = .80, P < .01), which made it possible to calculate the parenchymal drainage volume of these veins using their diameters alone.

CONCLUSION

Approximately half of the livers in this study had 1 or 2 accessory RHV(s), the parenchymal drainage volume of which was substantial. We can calculate the parenchymal drainage volume from the diameter of each accessory RHV on CT, which enables liver surgeons to determine how to manage these hepatic veins.