Volume-Assisted Estimation of Remnant Liver Function Based on Gd-EOB-DTPA Enhanced MR Relaxometry: A Prospective Observational Trial

In the context of liver surgery, predicting postoperative liver dysfunction is essential. This study explored the potential of preoperative liver function assessment by MRI for predicting postoperative liver dysfunction and compared these results with the established indocyanine green (ICG) clearance test. This prospective study included patients undergoing liver resection with preoperative MRI planning. Liver function was quantified using T1 relaxometry and correlated with established liver function scores. The analysis revealed an improved model for predicting postoperative liver dysfunction, exhibiting an accuracy (ACC) of 0.79, surpassing the 0.70 of the preoperative ICG test, alongside a higher area under the curve (0.75). Notably, the proposed model also successfully predicted all cases of liver failure and showed potential in predicting liver synthesis dysfunction (ACC 0.78). This model showed promise in patient survival rates with a Hazard ratio of 0.87, underscoring its potential as a valuable tool for preoperative evaluation. The findings imply that MRI-based assessment of liver function can provide significant benefits in the early identification and management of patients at risk for postoperative liver dysfunction.

Dual Graft Living Donor Liver Transplantation for High Acuity Patients: A Single-Center Experience

Background

The outcomes of dual graft living donor liver transplantation (DGLDLT) in high acuity patients remain underreported. The objective of this study was to report long-term outcomes from a single center in this select group of patients.

Methods

This was a retrospective review of patients who underwent DGLDLT between 2012 and 2017 (n = 10). High acuity patients were defined as patients with model for end stage liver disease (MELD) ≥30 or Child Pugh score ≥11. We looked at 90-day morbidity and mortality and 5-year overall survival (OS).

Results

The median MELD score and Child Pugh score were 30 (26.7-35) and 11 (11-11.2). The median recipient weight was 105 (95.2-113.7) and ranged from 82 to 132 kg. Out of 10 patients, 4 (40%) required perioperative renal replacement therapy, and 8 (80%) required hospital admission for optimization. The estimated graft to recipient weight ratio (GRWR) with right lobe graft alone was <0.8 in all patients, between 0.75 and 0.65 in 5 (50%) patients, and <0.65 in 5 (50%) patients. The 90-day mortality was 3/10 (30%), and there were 3/10 (30%) deaths during long-term follow-up. Among 155 high acuity patients, the 1-year OS with standard LDLT, standard LDLT with GRWR <0.8, and DGLDLT was 82%, 76%, and 58%, respectively (P = 0.123). With a median follow-up of 40.6 (1.9-74.4) months, the 5-year OS for DGLDLT was 50%.

Conclusion

The use of DGLDLT in high acuity patients should be prudent and low GRWR grafts should be considered a viable alternative in selected patients.

Critical Role of LSEC in Post-Hepatectomy Liver Regeneration and Failure

Liver sinusoids are lined by liver sinusoidal endothelial cells (LSEC), which represent approximately 15 to 20% of the liver cells, but only 3% of the total liver volume. LSEC have unique functions, such as fluid filtration, blood vessel tone modulation, blood clotting, inflammatory cell recruitment, and metabolite and hormone trafficking. Different subtypes of liver endothelial cells are also known to control liver zonation and hepatocyte function. Here, we have reviewed the origin of LSEC, the different subtypes identified in the liver, as well as their renewal during homeostasis. The liver has the exceptional ability to regenerate from small remnants. The past decades have seen increasing awareness in the role of non-parenchymal cells in liver regeneration despite not being the most represented population. While a lot of knowledge has emerged, clarification is needed regarding the role of LSEC in sensing shear stress and on their participation in the inductive phase of regeneration by priming the hepatocytes and delivering mitogenic factors. It is also unclear if bone marrow-derived LSEC participate in the proliferative phase of liver regeneration. Similarly, data are scarce as to LSEC having a role in the termination phase of the regeneration process. Here, we review what is known about the interaction between LSEC and other liver cells during the different phases of liver regeneration. We next explain extended hepatectomy and small liver transplantation, which lead to "small for size syndrome" (SFSS), a lethal liver failure. SFSS is linked to endothelial denudation, necrosis, and lobular disturbance. Using the knowledge learned from partial hepatectomy studies on LSEC, we expose several techniques that are, or could be, used to avoid the "small for size syndrome" after extended hepatectomy or small liver transplantation.

Living Donor Liver Transplantation Using Small-for-Size Grafts: Does Size Really Matter?

BACKGROUND

In living donor liver transplantation (LDLT), graft-to-recipient weight ratio (GRWR) > 0.8% is perceived as the critical graft size. This lower limit of GRWR (0.8%) has been challenged over the last decade owing to the surgical refinements, especially related to inflow and outflow modulation techniques. Our aim was to compare the recipient outcome in small-for-size (GRWR < 0.8) versus normal-sized grafts (GRWR > 0.8) and to determine the risk factors for mortality when small-for-size grafts (SFSG) were used.

METHODS

Data of 200 transplant recipients and their donors were analyzed over a period of two years. Routine practice of harvesting middle hepatic vein (MHV) or reconstructing anterior sectoral veins into neo-MHV was followed during LDLT. Outcomes were compared in terms of mortality, hospital stay, ICU stay, and occurrence of various complications such as functional small-for-size syndrome (F-SFSS), hepatic artery thrombosis (HAT), early allograft dysfunction (EAD), portal vein thrombosis (PVT), and postoperative sepsis. A multivariate analysis was also done to determine the risk factors for mortality in both the groups.

RESULTS

Recipient and donor characteristics, intraoperative variables, and demographical data were comparable in both the groups (GRWR < 0.8 and GRWR ≥ 0.8). Postoperative 90-day mortality (15.5% vs. 22.85%), mean ICU stay (10 vs. 10.32 days), and mean hospital stay (21.4 vs. 20.76 days) were statistically similar in the groups. There was no difference in postoperative outcomes such as occurrence of SFSS, HAT, PVT, EAD, or sepsis between the groups. Thrombosis of MHV/reconstructed MHV was a risk factor for mortality in grafts with GRWR < 0.8 but not in those with GRWR > 0.8.

CONCLUSION

Graft survival after LDLT using a small-for-size right lobe graft (GRWR < 0.8%) is as good as with normal grafts. However, patency of anterior sectoral outflow by MHV or reconstructed MHV is crucial to maintain graft function when SFSG are used.

Is Portal Venous Pressure or Porto-systemic Gradient Really A Harbinger of Poor Outcomes After Living Donor Liver Transplantation?

BACKGROUND

Portal hyperperfusion as a cause of small for size syndrome (SFSS) after living donor liver transplantation (LDLT) remains controversial. Portal venous pressure (PVP) is often measured indirectly and may be confounded by central venous pressure (CVP).

METHODS

In 42 adult cirrhotics undergoing elective LDLT, PVP was measured by direct canulation of portal vein and porto systemic gradient (PSG) was obtained after subtracting CVP from PVP. None underwent portal inflow modulation. SFSS was looked in 27 patients after excluding 15 with technical complications.

RESULTS

Clinical features of SFSS found in 6 patients, 5 with graft recipient weight ratio (GRWR) > 0.8% and PVP < 20 mm of Hg. One with GRWR < 0.8% could truly be labeled as SFSS. Incidence of SFSS was not higher in patients with elevated PVP > 20 mm of Hg (14.3% vs 0%, P = 0.259) or PSG > 13 mm of Hg (33.3% vs 0%, P = 0.111). Intensive care unit (ICU) stay was longer in patients with elevated PVP (14.55 vs 9.13 days, P = 0.007) and PSG (16.8 vs 9.72 days, P = 0.009). There was no difference in graft functions, post-operative complications and mortality in first month post-LDLT.

CONCLUSION

Elevated PVP or PSG increased morbidity but neither predicted SFSS nor affected survival.

Challenges and Outcome of Left-lobe Liver Transplants in Adult Living Donor Liver Transplants

Adult-to-adult living donor liver transplant (LDLT) frequently depend on using the right-lobes of the donor for obtaining adequate graft-to-recipient weight ratio (GRWR) of over 0.8% in the recipient. However, left-lobes remain an important option in adults, since the morbidity in the donor is considerably less with left donor hepatectomy when compared with right side liver resection. Further benefits of left-lobes in LDLT include more predictable anatomy of the left hepatic duct and left portal vein, which are usually long and single resulting in easier anastomosis in the recipient. Likewise, left-lobe grafts are easier to implant with an excellent venous outflow through the combined orifice of left and middle hepatic vein, as opposed to the complex hepatic vein reconstruction required in right-lobe grafts. However, left hepatic artery is often multiple unlike the right hepatic artery. The holy grail of left-lobe transplants is avoidance of small for size syndrome (SFSS) in the recipients. The strategies for overcoming SFSS currently depend on circumventing portal hyperperfusion in the graft. Measurement of portal pressure and modulating it if high, by splenic artery ligation, splenectomy, or hemiportocaval shunts are proving successful in avoiding SFSS. The future aim in adult LDLT should be to use the left-lobe as much as possible for the benefit of the donor at the same time avoiding SFSS even at very low GRWR for the benefit of the recipient.