Is impaired hepatic arterial buffer response a risk factor for biliary anastomotic stricture in liver transplant recipients?

Revisiting the Prognostic Influences of Donor-Recipient Size Mismatch in Deceased Donor Liver Transplantation

Background

Liver transplantation (LT) outcomes are influenced by donor-recipient size mismatch. This study re-evaluated the impact on graft size discrepancies on survival outcomes.

Methods

Data from 53 389 adult LT recipients from the United Network for Organ Sharing database (2013-2022) were reviewed. The study population was divided by the body surface area index (BSAi), defined as the ratio of donor body surface area (BSA) to recipient BSA, into small-for-size (BSAi < 0.78), normal-for-size (BSAi 0.78-1.24), and large-for-size (BSAi > 1.24) grafts in deceased donor LT (SFSD, NFSD, and LFSD). Multivariate Cox regression and Kaplan-Meier survival analyses were conducted.

Results

The frequency of size mismatch in deceased donor LT increased over the past 10 y. SFSD had significantly worse 90-d graft survival (P < 0.01), and LFSD had inferior 1-y graft survival among 90-d survivors (P = 0.01). SFSD was hazardous within 90 d post-LT because of vascular complications. Beyond 1 y, graft size did not affect graft survival. LFSD risk within the first year was mitigated with lower model for end-stage liver disease (MELD) 3.0 scores (<35) or shorter cold ischemia time (<8 h).

Conclusions

The negative impacts on donor-recipient size mismatch on survival outcomes are confined to the first year post-LT. SFSD is associated with a slight decrease in 90-d survival rates. LFSD should be utilized more frequently by minimizing cold ischemia time to <8 h, particularly in patients with MELD 3.0 scores below 35. These findings could improve donor-recipient matching and enhance LT outcomes.

Role of the immune system in liver transplantation and its implications for therapeutic interventions

Liver transplantation (LT) stands as the gold standard for treating end-stage liver disease and hepatocellular carcinoma, yet postoperative complications continue to impact survival rates. The liver's unique immune system, governed by a microenvironment of diverse immune cells, is disrupted during processes like ischemia-reperfusion injury posttransplantation, leading to immune imbalance, inflammation, and subsequent complications. In the posttransplantation period, immune cells within the liver collaboratively foster a tolerant environment, crucial for immune tolerance and liver regeneration. While clinical trials exploring cell therapy for LT complications exist, a comprehensive summary is lacking. This review provides an insight into the intricacies of the liver's immune microenvironment, with a specific focus on macrophages and T cells as primary immune players. Delving into the immunological dynamics at different stages of LT, we explore the disruptions after LT and subsequent immune responses. Focusing on immune cell targeting for treating liver transplant complications, we provide a comprehensive summary of ongoing clinical trials in this domain, especially cell therapies. Furthermore, we offer innovative treatment strategies that leverage the opportunities and prospects identified in the therapeutic landscape. This review seeks to advance our understanding of LT immunology and steer the development of precise therapies for postoperative complications.

Full-Right Full-Left Split Liver Transplantation for Two Adult Recipients: A Single-Center Experience in China

BACKGROUND

The most effective treatment for end-stage liver diseases is liver transplantation, which is impeded by the shortage of donor livers. Split liver transplantation (SLT) is important for addressing the donor liver shortage. However, full-right full-left SLT for two adult recipients is globally rarely conducted. This study aimed to investigate the clinical outcomes of this technique.

METHODS

We retrospectively analyzed the clinical data of 22 recipients who underwent full-right full-left SLT at Shulan (Hangzhou) Hospital between January, 2021 and September, 2022. The graft-to-recipient weight ratio (GRWR), cold ischemia time, operation time, length of the anhepatic phase, intraoperative blood loss, and red blood cell transfusion amount were all analyzed. The differences in liver function recovery after transplantation were compared between the left and right hemiliver groups. The postoperative complications and prognosis of the recipients were also analyzed.

RESULTS

The livers of 11 donors were transplanted into 22 adult recipients. The GRWR ranged from 1.16-1.65%, the cold ischemia time was 282.86 ± 134.87 min, the operation time was 371.32 ± 75.36 min, the anhepatic phase lasted 60.73 ± 19.00 min, the intraoperative blood loss was 759.09 ± 316.84 mL, and the red blood cell transfusion amount was 695.45 ± 393.67 mL. No significant difference in the levels of liver function markers, total bilirubin, aspartate aminotransferase, or alanine aminotransferase between left and right hemiliver groups at 1, 3, 5, 7, 14, and 28 d postoperatively was observed (both p > 0.05). One recipient developed bile leakage 10 d after transplantation, which improved with endoscopic retrograde cholangiopancreatography-guided nasobiliary drainage and stent placement. Another developed portal vein thrombosis 12 d after transplantation and underwent portal vein thrombectomy and stenting to restore portal vein blood flow. A color Doppler ultrasound performed 2 d after transplantation revealed hepatic artery thrombosis in one patient, and thrombolytic therapy was administered to restore hepatic artery blood flow. The liver function of other patients recovered quickly after transplantation.

CONCLUSIONS

Full-right full-left SLT for two adult patients is an efficient way to increase the donor pool. It is safe and feasible with careful donor and recipient selection. Transplant hospitals with highly experienced surgeons in SLT are recommended to promote using full-right full-left SLT for two adult recipients.

The Role of Microbiota in Liver Transplantation and Liver Transplantation-Related Biliary Complications

Liver transplantation as a treatment option for end-stage liver diseases is associated with a relevant risk for complications. On the one hand, immunological factors and associated chronic graft rejection are major causes of morbidity and carry an increased risk of mortality due to liver graft failure. On the other hand, infectious complications have a major impact on patient outcomes. In addition, abdominal or pulmonary infections, and biliary complications, including cholangitis, are common complications in patients after liver transplantation and can also be associated with a risk for mortality. Thereby, these patients already suffer from gut dysbiosis at the time of liver transplantation due to their severe underlying disease, causing end-stage liver failure. Despite an impaired gut-liver axis, repeated antibiotic therapies can cause major changes in the gut microbiome. Due to repeated biliary interventions, the biliary tract is often colonized by several bacteria with a high risk for multi-drug resistant germs causing local and systemic infections before and after liver transplantation. Growing evidence about the role of gut microbiota in the perioperative course and their impact on patient outcomes in liver transplantation is available. However, data about biliary microbiota and their impact on infectious and biliary complications are still sparse. In this comprehensive review, we compile the current evidence for the role of microbiome research in liver transplantation with a focus on biliary complications and infections due to multi-drug resistant germs.

Biliary complications after adult to adult right-lobe living donor liver transplantation (A-ARLLDLT): Analysis of 245 cases during 16 years period at a single high centre- A retrospective cohort study

Objectives

Biliary complications (BCs) after adult to adult living donor liver transplantation (A-ALDLT) result in poor graft and patient survival. This study aimed to analyze these complications.

Methods

We retrospectively analyzed BCs in 245 recipients who underwent A-ALDLT using the right–lobe graft during 16 years period in our centre. The overall male/female ratio was 215/30.

Results

One hundred fifty-five BCs affected 102 of our recipients (95 early (≤3months) and 60 late (≥3months)). They were classified as 67/245(27.3%) early bile leak, 10/245(4.1%) early biliary stricture, 44/245(17.9%) late biliary stricture, 4/245(1.6%) early cholangitis, 10/245(4.1%) late cholangitis, 14/245(5.7%) early biloma, and 6/245(2.4%) late cholangitic abscesses. Multiple biliary anastomoses were independently correlated with Post liver transplantation (LT) overall BCs; moreover, post LT hepatic artery thrombosis or stenosis (HAT/S) was an independent predictor of overall BCs, strictures and leaks. The mortality affected 96(39.2%) cases mostly due to sepsis, bleeding and multi-organ failure (MOF). On the other hand, the biliary related mortality was 10.6% of cases. Multiple cholangitic hepatic abscesses were significant predictors of poor graft and patient outcomes. Conclusions: Multiple biliary anastomoses and post LT HAT/S lead to a poor biliary outcome, furthermore, cholangitis, cholangitic abscesses and sepsis lead to poor graft and patient outcomes, so proper management of those variables is mandatory to improve outcomes after A-ARLLDLT.

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Multiple biliary anastomoses had negative insult on biliary outcomes after A-ARLLDLT.

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Post LT HAT/S lead to poor biliary outcomes after A-ARLLDLT.

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Cholangitis, and cholangitic abscesses lead to post LT poor graft and patient outcomes.

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Sepsis lead to post LT poor graft and patient outcomes.

The Prognostic Utility of Intraoperative Allograft Vascular Inflow Measurements in Donation After Circulatory Death Liver Transplantation

Donation after circulatory death (DCD) liver transplantation improves deceased donor liver use and decreases waitlist burden, albeit at an increased risk of biliary complications and inferior graft survival. Employing liver vascular inflow measurements intraoperatively permits allograft prognostication. However, its use in DCD liver transplantation is hitherto largely unknown and further explored here. DCD liver transplantation patient records at a single center from 2005 to 2018 were retrospectively scrutinized. Intraoperative flow data and relevant donor parameters were analyzed against endpoints of biliary events and graft survival. A total of 138 cases were chosen. The incidence of cumulative biliary complications was 38%, the majority of which were anastomotic strictures and managed successfully by endoscopic means. The ischemic cholangiopathy rate was 6%. At median thresholds of a portal vein (PV) flow rate of <92 mL/minute/100 g and buffer capacity (BC) of >0.04, both variables were independently associated with risk of biliary events (P = 0.01 and 0.04, respectively). Graft survival was 90% at 12 months and 75% at 5 years. Cox regression analysis revealed a PV flow rate of <50 mL/minute/100 g as predictive of poorer graft survival (P = 0.01). Furthermore, 126 of these DCD livers were analyzed against a propensity-matched group of 378 contemporaneous donation after brain death liver allografts (1:3), revealing significantly higher rates (P < 0.001) of both early allograft dysfunction (70% versus 30%) and biliary complications (37% versus 20%) in the former group. Although flow data were comparable between both sets, PV flow and BC were predictive of biliary events only in the DCD cohort. Intraoperative inflow measurements therefore provide valuable prognostication on biliary/graft outcomes in DCD liver transplantation, can help inform graft surveillance, and its routine use is recommended.

Risk Factors for Development of Biliary Stricture After Liver Transplant in Adult Patients: A Single-Center Retrospective Study

Identification of risk factors for biliary stricture after liver transplant and its potential prevention is crucial to improve the outcomes and reduce the complications. We retrospectively analyzed donor and recipient characteristics with intraoperative and postoperative parameters to identify the risk factors for development of post-transplant anastomotic and nonanastomotic biliary strictures with additional analysis of the time onset of those strictures. A total of 412 patients were included in this study. Mean (SD) follow-up time was 79 (35) months (range, 1-152 months). Biliary stricture was diagnosed in 84 patients (20.4%). Multivariate analysis indicated that postoperative biliary leakage (odd ratio [OR], 3.94; P = .001), acute cellular rejection (OR, 3.05; P < .001), donor age older than 47.5 years (OR, 2.05; P = .032), preoperative recipient platelet value < 77.5 × 10³/mL (OR, 1.91; P = .023), University of Wisconsin solution (OR, 1.73; P = .041)), recipient male sex (OR, 1.78; P = .072), portal/arterial flow ratio > 4 (OR, 1.76; P = .083), and intraoperative bleeding > 2850 mL (OR, 1.70; P = .053) were independent risk factors for biliary stricture regardless of the time of their appearance. Multiple risk factors for biliary stricture were determined in this study. Some of these risk factors are preventable, and implementation of strategies to eliminate some of those factors should reduce the development of post-transplant biliary stricture.

Post-operative assessment in patients after liver transplantation: imaging parameters associated with 1-year graft failure

PURPOSE

To identify post-liver transplant CT findings which predict graft failure within 1 year.

MATERIALS AND METHODS

We evaluated the CT scans of 202 adult liver transplants performed in our institution who underwent CT within 3 months after transplantation. We recorded CT findings of liver perfusion defect (LPD), parenchymal homogeneity, and the diameters and attenuations of the hepatic vessels. Findings were correlated to 1-year graft failure, and interobserver variability was assessed.

RESULTS

Forty-one (20.3%) of the 202 liver grafts failed within 1 year. Graft failure was highly associated with LPD (n = 18/25, or 67%, versus 15/98, or 15%, p < 0.001), parenchymal hypoattenuation (n = 20/41, or 48.8% versus 17/161, or 10.6%, p < 0.001), and smaller diameter of portal veins (right portal vein [RPV], 10.7 ± 2.7 mm versus 14.7 ± 2.2 mm, and left portal vein [LPV], 9.8 ± 3.0 mm versus 12.4 ± 2.2 mm, p < 0.001, respectively). Of these findings, LPD (hazard ratio [HR], 5.43, p < 0.001) and small portal vein diameters (HR, RPV, 3.33, p < 0.001, and LPV, 3.13, p < 0.05) independently predicted graft failure. All the measurements showed fair to moderate interobserver agreement (0.233~0.597).

CONCLUSION

For patients who have CT scan within the first 3 months of liver transplantation, findings of LPD and small portal vein diameters predict 1-year graft failure.

KEY POINTS

•Failed grafts are highly associated with liver perfusion defect, hypoattenuation, and small portal vein. •Right portal vein < 11.5 mm and left portal vein < 10.0 mm were associated with poor graft outcome. •Liver perfusion defect and small portal vein diameter independently predicted graft failure.

Does graft hemodynamics affect the risk of hepatocellular carcinoma recurrence after liver transplantation?

Although experimental studies have reported that hepatic ischemia-reperfusion injury promotes tumor growth and metastases, the impact of graft hemodynamics on the recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) is unclear. To investigate the association between graft hemodynamics and HCC recurrence after LT, we conducted a retrospective analysis of 279 patients who underwent LT for HCC. Graft hemodynamics including portal vein flow (PVF), hepatic artery flow (HAF), and total hepatic flow (THF) was analyzed as a predictor of HCC recurrence, using competing risk regression analyses. The cutoff values of PVF, HAF, and THF were set at the lower quartile of distribution. A cumulative recurrence curve demonstrated that low THF (<1511 mL/min, P = .005) was significantly associated with increased recurrence, whereas neither low PVF (<1230 mL/min, P = .150) nor low HAF (<164 mL/min, P = .110) was significant. On multivariate analysis, outside Milan criteria (sub-hazard ratio [SHR] = 3.742; P < .001), microvascular invasion (SHR = 3.698; P < .001), and low THF (SHR = 2.359; P = .010) were independently associated with increased HCC recurrence. In conclusion, our findings suggest that graft hemodynamics may play an important role in HCC recurrence after LT.

Applicability of Hypothermic Oxygenate Machine Perfusion Preservation for Split-Liver Transplantation in a Porcine Model: An Experimental Study

Background

Split-liver transplantation can be useful in situations of limited donor resources. However, novel preservation methods are required to help the recipient recover from severe ischemic reperfusion injury incurred due to receiving a relatively small liver graft.

Material/Methods

Our experiment was performed using porcine livers without warm ischemia time, assuming a brain-dead organ. We made porcine split-liver grafts by 75% liver resection at the back table and divided the specimens into 4 groups. Group 1 was preserved with simple cold storage after splitting (CS; n=3), Group 2 was preserved with hypothermic perfusion preservation (HMP) after splitting (SBP; n=3), Group 3 was preserved with HMP after splitting under perfusion preservation (SDP; n=4), and Group 4 had the whole liver perfused as control grafts (Whole Liver; n=3). To assess potential methods of preservation and their effects, all grafts were evaluated by an ex vivo isolated liver reperfusion model using diluted autologous blood.

Results

Portal vein pressure resistances during reperfusion were low in Group3 (SDP). Hepatic artery pressure resistances during reperfusion were markedly higher in Group 1(CS) than in the other groups. The levels of AST and LDH were high and increased at 2 h after reperfusion in Group 1 (CS). The histological findings show that the liver cell structure was irregular in Group 1 (CS) but remained regular in Groups 2 (SBP) and 3 (SDP). Histological Suzuki scores were also significantly better in Groups 2 (SBP) and 3 (SDP) compared with Group 1 (CS).

Conclusions

Splitting the liver under machine perfusion preservation may help restore the function and reduce ischemia-reperfusion injury.

Predictive Value of Hepatic Venous Pressure Gradient for Graft Hemodynamics in Living Donor Liver Transplantation

The hepatic venous pressure gradient (HVPG) measurement is known to correlate with the severity of portal hypertension in patients with liver cirrhosis. This retrospective study investigated the clinical value of preoperative measurement of HVPG in patients who underwent adult-to-adult living donor liver transplantation (LDLT) and its predictive value for hepatic hemodynamics after graft reperfusion. For this study, 75 patients who underwent adult-to-adult LDLT were divided into 2 groups (HVPG <16 mm Hg or HVPG ≥16 mm Hg) to investigate the correlation between preoperative HVPG and characteristics and surgical outcomes of the patients, including portal vein flow (PVF) and hepatic artery flow (HAF) after graft reperfusion. In total, 35 (46.7%) patients had an HVPG ≥16 mm Hg. These patients had significantly higher international normalized ratio values, serum creatinine levels, and Model for End-Stage Liver Disease scores compared with the 40 patients with HVPG <16 mm Hg. They also had higher rates of variceal bleeding, encephalopathy, and intractable ascites as well as lower serum albumin levels and platelet counts compared with those patients with HVPG <16 mm Hg. Portal inflow modulation (PIM) was frequently performed in the patients with HVPG ≥16 mm Hg compared with those with HVPG <16 mm Hg. No significant differences in surgical outcomes after LDLT were found between these 2 groups except for postoperative ascites. Preoperative HVPG showed a positive correlation with PVF and a negative correlation with HAF after graft reperfusion (false discovery rate [FDR] P = 0.08 and FDR P = 0.08, respectively). In linear regression analyses, preoperative HVPG was independently associated with PVF after graft reperfusion. In conclusion, our findings indicate that preoperative HVPG is associated with hepatic hemodynamics after graft implantation in LDLT. HVPG as a routine preoperative evaluation may be helpful for surgical planning of PIM.

Prediction of biliary anastomotic stricture after deceased donor liver transplantation: the impact of platelet counts - a retrospective study

Biliary stricture is a common cause of morbidity after liver transplantation (LT). This study aimed to determine the risk factors for post-transplant biliary anastomotic strictures (BAS), focusing on perioperative platelet counts. We enrolled 771 consecutive recipients who underwent ABO-identical/compatible deceased donor LT with duct-to-duct biliary reconstruction from January 2000 to June 2012. BAS was identified in 142 cases. The median time for stricture development was 176 days. Preoperative and postoperative platelet counts within 5 days after LT were significantly lower in patients with BAS than those without BAS. Using cutoff values acquired by the receiver operating characteristic curve analysis, persistent postoperative thrombocytopenia was defined as platelet counts <41 × 1000/μl and <53 × 1000/μl on postoperative day (POD) 3 and POD 5, respectively. Multivariate analysis indicated persistent postoperative thrombocytopenia (OR = 2.38) was the only independent risk factor for BAS. No significant associations were observed in terms of donor and surgical factors. Multivariate analysis demonstrated estimated blood loss (OR = 1.01, per 100 ml) was an independent contributing factor for persistent postoperative thrombocytopenia. We demonstrated low platelet count was associated with progression of post-transplant BAS. Minimizing intraoperative blood loss potentially contributes to maintain post-transplant platelet count, which may reduce incidence of BAS.

Split liver transplantation in adults

Split liver transplantation (SLT), while widely accepted in pediatrics, remains underutilized in adults. Advancements in surgical techniques and donor-recipient matching, however, have allowed expansion of SLT from utilization of the right trisegment graft to now include use of the hemiliver graft as well. Despite less favorable outcomes in the early experience, better outcomes have been reported by experienced centers and have further validated the feasibility of SLT. Importantly, more than two decades of experience have identified key requirements for successful SLT in adults. When these requirements are met, SLT can achieve outcomes equivalent to those achieved with other types of liver transplantation for adults. However, substantial challenges, such as surgical techniques, logistics, and ethics, persist as ongoing barriers to further expansion of this highly complex procedure. This review outlines the current state of SLT in adults, focusing on donor and recipient selection based on physiology, surgical techniques, surgical outcomes, and ethical issues.

Complications and mortality after adult to adult living donor liver transplantation: A retrospective cohort study

BACKGROUND AND AIMS

Living donor liver transplantation (LDLT) is widely performed for patients to resolve the critical shortage of organs from cadavers. Despite rapid implementation of the procedure, both complications and mortality of LDLT are annoying problems. The aim of this study was to analyze complications and mortality of patients after adult to adult LDLT (A-ALDLT) in a single center.

METHODS

Between April 2003 and November 2013, 167 (A-ALDLT) recipients in National Liver Institute, Egypt were included. We retrospectively analyzed complications and mortality in them.

RESULTS

The overall incidence of complications was 86.2% (n = 144) and classified as biliary 43.7% (n = 73), vascular 21.6% (n = 36), Small for size syndrome (SFSS) 12.6% (n = 21), Gastrointestinal tract (GIT) 19.8% (n = 33), wound 12.6% (n = 21), chest 19.8% (n = 33), neurological 26.3% (n = 44), renal 21% (n = 35), intra abdominal collection 21.6% (n = 36), recurrent hepatitis C virus (HCV) 16.8% (n = 28), recurrent hepatocellular carcinoma (HCC) 2.4% (n = 4), acute rejection 19.2% (n = 32). 65 (45.1%) of 144 complicated patients died, while 10 (43.5%) of 23 non complicated died. The incidence of whole, in hospital and late mortalities were 44.9%, 28.7% and 16.2% respectively.

CONCLUSIONS

Mortality was higher among complicated cases where vascular complications and SFSS had significant effect on it so prevention and treatment of them is required for improving outcome.

Complications and mortality after adult to adult living donor liver transplantation: A retrospective cohort study

Background and aims

Living donor liver transplantation (LDLT) is widely performed for patients to resolve the critical shortage of organs from cadavers. Despite rapid implementation of the procedure, both complications and mortality of LDLT are annoying problems. The aim of this study was to analyze complications and mortality of patients after adult to adult LDLT (A-ALDLT) in a single center. Methods: Between April 2003 and November 2013, 167 (A-ALDLT) recipients in National Liver Institute, Egypt were included. We retrospectively analyzed complications and mortality in them.

Results

The overall incidence of complications was 86.2% (n = 144) and classified as biliary 43.7% (n = 73), vascular 21.6% (n = 36), Small for size syndrome (SFSS) 12.6% (n = 21), Gastrointestinal tract (GIT) 19.8% (n = 33), wound 12.6% (n = 21), chest 19.8% (n = 33), neurological 26.3% (n = 44), renal 21% (n = 35), intra abdominal collection 21.6% (n = 36), recurrent hepatitis C virus (HCV) 16.8% (n = 28), recurrent hepatocellular carcinoma (HCC) 2.4% (n = 4), acute rejection 19.2% (n = 32). 65 (45.1%) of 144 complicated patients died, while 10 (43.5%) of 23 non complicated died. The incidence of whole, in hospital and late mortalities were 44.9%, 28.7% and 16.2% respectively. Conclusions: Mortality was higher among complicated cases where vascular complications and SFSS had significant effect on it so prevention and treatment of them is required for improving outcome.

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Mortality was higher among complicated cases.

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Vascular complication was independent predictors of poor outcome.

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Small for size syndrome was independent predictors of poor outcome.

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Proper management of the previous complications improve outcome of LDLT.

Safety and efficacy of splenic artery embolization for portal hyperperfusion in liver transplant recipients: a 5-year experience

Severe portal hyperperfusion (PHP) after liver transplantation has been shown to cause intrahepatic arterial vasoconstriction secondary to increased adenosine washout (hepatic artery buffer response). Clinically, posttransplant PHP can cause severe cases of refractory ascites and hydrothorax. In the past, we reported our preliminary experience with the use of splenic artery embolization (SAE) as a way to reduce PHP. Here we present our 5-year experience with SAE in orthotopic liver transplantation (OLT). Between January 2007 and December 2011, 681 patients underwent OLT at our institution, and 54 of these patients underwent SAE for increased hepatic arterial resistance and PHP (n=42) or refractory ascites/hepatic hydrothorax (n=12). Patients undergoing SAE were compared to a control group matched by year of embolization, calculated Model for End-Stage Liver Disease score, and liver weight. SAE resulted in improvements in hepatic artery resistive indices (0.92±0.14 and 0.76±0.10 before and after SAE, respectively; P<0.001) and improved hepatic arterial blood flow (HAF; 15.6±9.69 and 28.7±14.83, respectively; P<0.001). Calculated splenic volumes and spleen/liver volume ratios were correlated with patients requiring SAE versus matched controls (P=0.002 and P=0.001, respectively). Among the 54 patients undergoing SAE, there was 1 case of postsplenectomy syndrome. No abscesses, significant infections, or bleeding was noted. We thus conclude that SAE is a safe and effective technique able to improve HAF parameters in patients with elevated portal venous flow and its sequelae.

Ratio of hepatic arterial flow to recipient body weight predicts biliary complications after deceased donor liver transplantation

OBJECTIVES

Adequate hepatic arterial (HA) flow to the bile duct is essential in liver transplantation. This study was conducted to determine if the ratio of directly measured HA flow to weight is related to the occurrence of biliary complications after deceased donor liver transplantation.

METHODS

A retrospective review of 2684 liver transplants carried out over a 25-year period was performed using data sourced from a prospectively maintained database. Rates of biliary complications (biliary leaks, anastomotic and non-anastomotic strictures) were compared between two groups of patients with HA flow by body weight of, respectively, <5 ml/min/kg (n = 884) and ≥5 ml/min/kg (n = 1800).

RESULTS

Patients with a lower ratio of HA flow to weight had higher body weight (92 kg versus 76 kg; P < 0.001) and lower HA flow (350 ml/min versus 550 ml/min; P < 0.001). A lower ratio of HA flow to weight was associated with higher rates of biliary complications at 2 months, 6 months and 12 months (19.8%, 28.2% and 31.9% versus 14.8%, 22.4% and 25.8%, respectively; P < 0.001).

CONCLUSIONS

A ratio of HA flow to weight of < 5 ml/min/kg is associated with higher rates of biliary complications. This ratio may be a useful parameter for application in the prevention and early detection of biliary complications.

[Small-for-size: experimental findings for liver surgery]

The characteristics of the hepatic macrocirculation, i.e., the parallel portal-venous and arterial blood supply, is of utmost relevance for liver surgery. With extended hepatectomy or transplantation of a reduced-size liver the remaining or transplanted liver tissue is overperfused because the liver fails to regulate the portal-venous inflow. This portal hyperperfusion is responsible for the initiation of liver cell proliferation but represents at the same time one of the substantial events in the pathogenesis of the small-for-size syndrome. Portal-venous hyperperfusion, the so-called hepatic arterial buffer response, which describes the semi-reciprocal relationship between the portal-venous and hepatic arterial blood flows, leads to an arterial hypoperfusion of the small-for-size liver. In this article experimental and clinical data are discussed which underline the high but so far overseen relevance of this arterial underperfusion in the development of a small-for-size syndrome.

Hemodynamic consequences of spontaneous splenorenal shunts in deceased donor liver transplantation

The presence of large spontaneous splenorenal shunts (SSRSs) is a risk factor for poor portal vein flow and liver dysfunction. The disconnection of splenorenal shunts by left renal vein (LRV) ligation has been suggested as a potential solution for improving portal flow. We reviewed the hemodynamic consequences of splenorenal shunts in deceased donor liver transplantation and investigated the role of LRV ligation. In 10 patients who underwent liver transplantation at our institution between January 2006 and April 2010, an SSRS was diagnosed preoperatively. Intraoperative portal and hepatic artery flows were measured with a transit time flowmeter. The shunt was disconnected in 6 patients for whom the portal flow after reperfusion was less than or equal to 1200 mL/minute. LRV ligation resulted in significant increases in the portal flow. There were no differences in renal function for the patients who underwent renal vein ligation and the patients who did not undergo ligation. In conclusion, LRV ligation disconnects splenorenal shunts and modulates the portal inflow without any detrimental effects on renal function.

Use of tissue plasminogen activator in liver transplantation from donation after cardiac death donors

Ischemic-type biliary stricture (ITBS) occurs in up to 50% after liver transplantation (LT) from donation after cardiac death (DCD) donors. Thrombus formation in the peribiliary microcirculation is a postulated mechanism. The aim was to describe our experience of tissue plasminogen activator (TPA) administration in DCD-LT. TPA was injected into the donor hepatic artery on the backtable (n = 22). Two recipients developed ITBS including one graft failure. Although excessive postreperfusion bleeding was seen in 14 recipients, the amount of TPA was comparable between those with and without excessive bleeding (6.4 ± 2.8 vs. 6.6 ± 2.8 mg, p = 0.78). However, donor age (41 ± 12 vs. 29 ± 9 years, p = 0.02), donor BMI (26.3 ± 5.5 vs. 21.7 ± 3.6 kg/m(2) , p = 0.03), previous laparotomy (50% vs. 0%, p = 0.02) and lactate after portal reperfusion (6.3 ± 4.6 vs. 2.8 ± 0.9 mmol/L, p = 0.005) were significantly greater in recipients with excessive bleeding. In conclusion, the use of TPA may lower the risk of ITBS-related graft failure in DCD-LT. Excessive bleeding may be related to poor graft quality and previous laparotomy rather than the amount of TPA. Further studies are needed in larger population.

Prospective evaluation of intraoperative hemodynamics in liver transplantation with whole, partial and DCD grafts

The interaction of systemic hemodynamics with hepatic flows at the time of liver transplantation (LT) has not been studied in a prospective uniform way for different types of grafts. We prospectively evaluated intraoperative hemodynamics of 103 whole and partial LT. Liver graft hemodynamics were measured using the ultrasound transit time method to obtain portal (PVF) and arterial (HAF) hepatic flow. Measurements were recorded on the native liver, the portocaval shunt, following reperfusion and after biliary anastomosis. After LT HAF and PVF do not immediately return to normal values. Increased PVF was observed after graft implantation. Living donor LT showed the highest compliance to portal hyperperfusion. The amount of liver perfusion seemed to be related to the quality of the graft. A positive correlation for HAF, PVF and total hepatic blood flow with cardiac output was found (p = 0.001). Portal hypertension, macrosteatosis >30%, warm ischemia time and cardiac output, independently influence the hepatic flows. These results highlight the role of systemic hemodynamic management in LT to optimize hepatic perfusion, particularly in LDLT and split LT, where the highest flows were registered.