Venovenous bypass in liver transplantation: Exploring the benefits, efficacy, and safety.

Venovenous bypass (VVB) is a technique used in liver transplantation (LT) to maintain hemodynamic stability and abdominal organ perfusion and thereby improve patient outcomes. Despite its perceived benefits, VVB utilization has declined globally due to concerns related to heparinization, major bleeding and the need for expertise. Recent advancements, such as percutaneous cannulation techniques and improved extracorporeal technology have improved the safety of VVB in LT. This paper presents a modified VVB circuit with enhanced safety features. Cannulation plays a pivotal role in VVB establishment, with percutaneous methods increasingly favored. Studies demonstrate VVB's efficacy in improving patient outcomes with lower incidence of acute kidney injury and reduced operative time and blood loss, with no added morbidity or mortality. However, its routine use faces challenges, with alternative techniques gaining traction. Our experience highlights VVB's role in various clinical scenarios, including patients with high Model for End-Stage Liver Disease (MELD) scores, challenging surgical anatomy, portal vein thrombosis and pre-existing cardiovascular disease, emphasizing its safety and efficacy. Continued research is needed to optimize VVB techniques and ensure better outcomes for liver transplant recipients.

Pancreatic schwannoma: a rare differential diagnosis for a pancreatic mass.

Pancreatic schwannomas are rare benign tumors with low malignant potential and are often difficult to diagnose due to their non-specific presenting symptoms and overlapping radiological imaging characteristics. Cross-sectional imaging plays an important role in the initial diagnosis and in delineating the extent of the lesion. However, biopsy and histopathological examination remains the gold-standard for a definite diagnosis. The management of pancreatic schwannomas includes surgical resection often yielding excellent clinical outcomes with low recurrence rates. We present a case of a 33-year-old female patient with a history of a recurrent vague upper abdominal pain where CT of the upper abdomen showed a hypodense pancreatic mass. Robotic subtotal pancreatectomy was done with histopathology showing spindled Schwann cells indicative of a pancreatic schwannoma.

Living Donor Liver Transplantation With Augmented Venous Outflow and Splenectomy: A Promised Land for Small Left Lobe Grafts.

OBJECTIVE: Living donor liver transplantation (LDLT) using small grafts, especially left lobe grafts (H1234-MHV) (LLG), continues to be a challenge due to small-for-size syndrome (SFSS). We herein demonstrate that with surgical modifications, outcomes with small grafts can be improved. METHODS: Between 2012 and 2020, we performed 130 adult LDLT using 61 (47%) LLG (H1234-MHV) in a single Enterprise. The median graft-to-recipient weight ratio was 0.84%, with graft-to-recipient weight ratio <0.7% accounting for 22%. Splenectomy was performed in 72 (56%) patients for inflow modulation before (n=50) or after (n=22) graft reperfusion. In LLG-LDLT, venous outflow was achieved using all three recipient hepatic veins. In right lobe graft (H5678) (RLG)-LDLT, the augmented graft right hepatic vein was anastomosed to the recipient's cava with a large cavotomy. Outcome measures include SFSS, early allograft dysfunction (EAD), and survival. RESULTS: Graft survival rates at 1, 3, and 5 years were 94%, 90%, and 83%, respectively, with no differences between LLG (H1234-MHV) and RLG (H5678). Splenectomy significantly reduced portal flow without increasing the complication rate. Despite the aggressive use of small grafts, SFSS and EAD developed in only 1 (0.8%) and 18 (13.8%) patients, respectively. Multivariable logistic regression revealed model for end-stage liver disease score and LLG (H1234-MHV) as independent risk factors for EAD and splenectomy as a protective factor (odds ratio: 0.09; P =0.03). For LLG (H1234-MHV)-LDLT, patients who underwent prereperfusion splenectomy tended to have better 1-year graft survival than those receiving postreperfusion splenectomy. CONCLUSIONS: LLG (H1234-MHV) are feasible in adult LDLT with excellent outcomes comparable to RLG (H5678). Venous outflow augmentation and splenectomy help lower the threshold of using small-for-size grafts without compromising graft survival.

Ex Situ Liver Machine Perfusion: The Impact of Fresh Frozen Plasma.

The primary aim of this single-center, phase 1 exploratory study was to investigate the safety, feasibility, and impact on intrahepatic hemodynamics of a fresh frozen plasma (FFP)-based perfusate in ex situ liver normothermic machine perfusion (NMP) preservation. Using an institutionally developed perfusion device, 21 livers (13 donations after brain death and 8 donations after circulatory death) were perfused for 3 hours 21 minutes to 7 hours 52 minutes and successfully transplanted. Outcomes were compared in a 1:4 ratio to historical control patients matched according to donor and recipient characteristics and preservation time. Perfused livers presented a very low resistance state with high flow during ex situ perfusion (arterial and portal flows 340 ± 150 and 890 ± 70 mL/minute/kg liver, respectively). This hemodynamic state was maintained even after reperfusion as demonstrated by higher arterial flow observed in the NMP group compared with control patients (220 ± 120 versus 160 ± 80 mL/minute/kg liver, P = 0.03). The early allograft dysfunction (EAD) rate, peak alanine aminotransferase (ALT), and peak aspartate aminotransferase (AST) levels within 7 days after transplantation were lower in the NMP group compared with the control patients (EAD 19% versus 46%, P = 0.02; peak ALT 363 ± 318 versus 1021 ± 999 U/L, P = 0.001; peak AST 1357 ± 1492 versus 2615 ± 2541 U/L, P = 0.001 of the NMP and control groups, respectively). No patient developed ischemic type biliary stricture. One patient died, and all other patients are alive and well at a follow-up of 12-35 months. No device-related adverse events were recorded. In conclusion, with this study, we showed that ex situ NMP of human livers can be performed safely and effectively using a noncommercial device and an FFP-based preservation solution. Future studies should further investigate the impact of an FFP-based perfusion solution on liver hemodynamics during ex situ normothermic machine preservation.

Elevated Risk of Split-Liver grafts in adult liver Transplantation: Statistical Artifact or Nature of the Beast?

A recent study using US national registry data reported, using Cox proportional hazards (PH) models, that split-liver transplantation (SLT) has improved over time and is no more hazardous than whole-liver transplantation (WLT). However, the study methods violated the PH assumption, which is the fundamental assumption of Cox modeling. As a result, the reported hazard ratios (HRs) are biased and unreliable. This study aimed to investigate whether the risk of graft survival (GS) in SLT has really improved over time, ensuring attention to the PH assumption. This study included 80,998 adult deceased donor liver transplantation (LT) (1998-2015) from the Scientific Registry Transplant Recipient. The study period was divided into 3 time periods: era 1 (January 1998 to February 2002), era 2 (March 2002 to December 2008), and era 3 (January 2009 to December 2015). The PH assumption was tested using Schoenfeld's test, and where the HR of SLT violated the assumption, changes in risk for SLT over time from transplant were assessed. SLT was performed in 1098 (1.4%) patients, whereas WLT was used in 79,900 patients. In the Cox PH analysis, the P values of Schoenfeld's global tests were <0.05 in all eras, which is consistent with deviation from proportionality. Assessing HRs of SLT with a time-varying effect, multiple Cox models were conducted for post-LT intervals. The HR curves plotted according to time from transplant were higher in the early period and then decreased at approximately 1 year and continued to decrease in all eras. For 1-year GS, the HRs of SLT were 1.92 in era 1, 1.52 in era 2, and 1.47 in era 3 (all P < 0.05). In conclusion, the risk of SLT has a time-varying effect and is highest in the early post-LT period. The risk of SLT is underestimated if it is evaluated by overall GS. SLT was still hazardous if the PH assumption was considered, although it became safer over time.

Lipid metabolism and functional assessment of discarded human livers with steatosis undergoing 24 hours of normothermic machine perfusion.

Normothermic machine perfusion (NMP) is an emerging technology to preserve liver allografts more effectively than cold storage (CS). However, little is known about the effect of NMP on steatosis and the markers indicative of hepatic quality during NMP. To address these points, we perfused 10 discarded human livers with oxygenated NMP for 24 hours after 4-6 hours of CS. All livers had a variable degree of steatosis at baseline. The perfusate consisted of packed red blood cells and fresh frozen plasma. Perfusate analysis showed an increase in triglyceride levels from the 1st hour (median, 127 mg/dL; interquartile range [IQR], 95-149 mg/dL) to 24th hour of perfusion (median, 203 mg/dL; IQR, 171-304 mg/dL; P = 0.004), but tissue steatosis did not decrease. Five livers produced a significant amount of bile (≥5 mL/hour) consistently throughout 24 hours of NMP. Lactate in the perfusate cleared to <3 mmol/L in most livers within 4-8 hours of NMP, which was independent of bile production rate. This is the first study to characterize the lipid profile and functional assessment of discarded human livers at 24 hours of NMP. Liver Transplantation 24 233-245 2018 AASLD.

Impact of Temperature on Porcine Liver Machine Perfusion From Donors After Cardiac Death.

Normothermic machine perfusion (NMP) has been introduced as a promising technology to preserve and possibly repair marginal liver grafts. The aim of this study was to compare the effect of temperature on the preservation of donation after cardiac death (DCD) liver grafts in an ex vivo perfusion model after NMP (38.5°C) and subnormothermic machine perfusion (SNMP, 21°C) with a control group preserved by cold storage (CS, 4°C). Fifteen porcine livers with 60 min of warm ischemia were preserved for 10 h by NMP, SNMP or CS (n = 5/group). After the preservation phase all livers were reperfused for 24 h in an isolated perfusion system with whole blood at 38.5°C to simulate transplantation. At the end of transplant simulation, the NMP group showed significantly lower hepatocellular enzyme level (AST: 277 ± 69 U/L; ALT: 22 ± 2 U/L; P < 0.03) compared to both SNMP (AST: 3243 ± 1048 U/L; ALT: 127 ± 70 U/L) and CS (AST: 3150 ± 1546 U/L; ALT: 185 ± 97 U/L). There was no significant difference between SNMP and CS. Bile production was significantly higher in the NMP group (219 ± 43 mL; P < 0.01) compared to both SNMP (49 ± 84 mL) and CS (12 ± 16 mL) with no significant difference between the latter two groups. Histologically, the NMP livers showed preserved cellular architecture compared to the SNMP and CS groups. NMP was able to recover DCD livers showing superior hepatocellular integrity, biliary function, and microcirculation compared to SNMP and CS. SNMP showed some significant benefit over CS, yet has not shown any advantage over NMP.

Abdominal wall reconstruction with intraperitoneal prosthesis in desmoid tumors surgery.

Desmoid tumor (DT), also known as aggressive fibromatosis, is a rare soft tissue neoplasm. For those tumors localized in the anterior abdominal wall, radical resection and reconstruction with mesh are indicated. Due to the rarity of this disease, there have been no randomized trials, but in reported retrospective series, although it is considered a benign lesion, it is clear that local recurrence is not uncommon. Records from seven consecutive patients (1 man, 6 women; mean age 35 years, range 25-60 years) presenting with desmoid tumors of the anterior abdominal wall were analyzed. In all cases the surgical strategy was the same: wide surgical excision and immediate plastic reconstruction with ePTFE mesh after intraoperative confirmation by frozen section of disease-free margins >1 cm. No immediate postoperative complications were recorded, and no patients developed recurrence after a median follow-up period of 60 months. The long-term mean of global health status recorded was 100%. Radical resection aided by intraoperative margin evaluation by frozen sections, followed by immediate mesh reconstruction, is a safe procedure and can provide a definitive cure without functional limitations for patients with desmoid tumors of the anterior abdominal wall.