Circumferential Fence With the Use of Polyethylene Terephthalate (Dacron) Vascular Graft for All-in-One Hepatic Venous Reconstruction in Right-Lobe Living-Donor Liver Transplantation

Particular Chinese contributions to extracorporeal liver surgery

Extracorporeal liver surgery (ELS), also known as liver autotransplantation, is a hybrid (cross-fertilized) surgery incorporating the technical knowledge from extreme liver and transplant liver surgeries, and recently became more embraced and popularized among leading centers. ELS could be summarized into three major categories, namely, ex-situ liver resection and autotransplantation (ELRA), ante-situm liver resection and autotransplantation (ALRA) and auxiliary partial liver autotransplantation (APLA). The successful development of ELS during the past 37 years is definitely inseparable from continuous efforts done by Chinese surgeons and researchers. Especially, the precision liver surgery paradigm has allowed to transform ELS into a modularized, more simplified, and standardized surgery, to upgrade surgical skills, to improve peri-operative outcome and long-term survival, to increase the capability of surgeons to select more complex diseases and to expand the level of medical service to the population. This review highlights the Chinese contributions to the field of ELS, focusing thereby on features of different surgical types, technical innovations, disease selection and surgical indication, patient prognosis and future perspectives.

Optical Anisotropy of Polyethylene Terephthalate Films Characterized by Spectral Means

Polyethylene terephthalate (PET) films are the subject of intensive research because of great interest in using them in applications, especially in medicine. From an optical point of view, PET films with a low degree of stretching can be considered uniaxial materials, for which the determination of the linear birefringence and its dispersion is very important. Two methods were applied here for the estimation of these parameters: the ellipsometric method and the channeled spectra method. The ellipsometric method uses monochromatic radiation; therefore, the linear birefringence of the PET films is determined for a given value of the radiation wavelength. The channeled spectra method allows for the estimation of the linear birefringence and its dispersion for a large range of wavelengths in the visible spectrum. A decrease in both parameters with the increase in the wavelength was recorded. To evidence the microstructure of PET films and the conformational changes induced by elongation and to evaluate the degree of orientation, a polarized infrared spectral study in attenuated total reflection (ATR-FTIR) mode was performed. The dichroic ratio (between the absorbance measured with linearly polarized radiation parallel and orthogonal relative to the stretching direction, respectively) and the ATR absorbance ratio for the machine direction (MD) and transversal direction (TD) configurations both for the stretched and unstretched PET samples were measured.

Comparison of Postoperative Hemorrhage Risk After Partial Liver Transplantation Versus Whole Liver Transplantation: A Single-Center Experience

BACKGROUND

We aimed to identify risk factors associated with reoperation for postoperative intraperitoneal hemorrhage (PIH) after orthotopic liver transplantation and investigate if partial liver transplantation (PLT) increases the risk of PIH.

METHODS

We retrospectively analyzed the medical records of 304 consecutive recipients who underwent orthotopic liver transplantation at the Affiliated Lihuili Hospital, Ningbo University, from January 2016 to July 2022. Data were compared between recipients who experienced PIH requiring reoperation and those who did not. Subgroup propensity score matching analysis was performed to assess the impact of PLT on PIH risk. Neither prisoners nor participants who were coerced or paid were used in the study.

RESULTS

Among the 304 recipients, 22 (7.2%) underwent reoperation for PIH. Multivariate analysis revealed that the recipient Model for End-Stage Liver Disease (MELD) score (odds ratio = 1.066, 95% CI [1.025-1.109], P = .001) and volume of intraoperative packed red blood cell transfusion (odds ratio = 1.089, 95% CI [1.032-1.481], P = .002) were independent risk factors for PIH. No significant differences were observed in the risk of PIH between PLT and whole liver transplantation.

CONCLUSION

Preoperative MELD score and intraoperative packed red blood cell transfusion should be carefully considered to manage the risk of PIH in liver transplantation recipients. Partial liver transplantation, a crucial approach for addressing donor shortages, does not increase the risk of reoperation for PIH in recipients.

Measurement of oxidant and antioxidant levels in liver tissue obtained from patients with liver transplantation: A case-control study

OBJECTIVE

This study aimed to compare oxidant and antioxidant substance accumulation in the liver tissues of patients with chronic liver disease (recipients) who underwent liver transplantation (LT) with living liver donors (LLDs) who underwent living donor hepatectomy (LDH).

METHODS

This prospective study included 160 recipients (LT group) and 40 LLDs (LLD group). During surgery, a piece of liver tissue measuring a minimum of 10 × 10 mm was obtained from the edge of the right lobe of the liver of recipients and LLDs, incubated for 10 min in saline to remove blood, and stored at -70 °C until biochemical analysis was performed. Catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), myeloperoxidase (MPO), prolidase, reduced glutathione (GSH), malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), total thiol, native thiol, and disulfide levels were measured in stored liver tissues.

RESULTS

There was a statistically significant difference between LT and LLD groups in terms of age (p < 0.001), body mass index (p = 0.019), GSH-Px (p < 0.001), SOD (p = 0.001), MPO (p < 0.001), prolidase (p < 0.001), GSH (p < 0.001), and MDA (p = 0.003) values in favor of the LT group. Furthermore, there was a statistically significant difference between LT and LLD groups in terms of CAT (p < 0.001), TAS (p < 0.001), TOS (p < 0.001), OSI (p < 0.001), total thiol (p < 0.001), native thiol (p < 0.001), and disulfide (p < 0.001) values in favor of the LLD group. There were no differences between the groups in terms of sex.

CONCLUSION

This study demonstrated that it is possible to assess the extent of oxidative stress in liver tissues by measuring the levels of antioxidant enzymes, oxidants, or the end-products of oxidative stress. With the use of optimum and minimally invasive methods, quantifying these molecules will potentially help evaluate the extent of liver disease and prognostication of liver cirrhosis.

From liver surgery to liver transplant surgery: new developments in autotransplantation

PURPOSE OF REVIEW

In spite of substantial technical improvements and conceptual revolutions in advanced liver surgery, there are still straitened circumstances that pose difficulties for in-situ liver resections. Ex-vivo liver resection and autotransplantation (ELRA) is a hybrid technique combining experiences from conventional liver surgery and liver transplantation. This technique is becoming more comprehensive and popular among leading centers recently.

RECENT FINDINGS

Short-term and long-term outcomes are now the focus of the technique after more than a decade of cumulative progress and technical evolution. As the 5-year survival nowadays reaches over 80%, this technique is believed to be beneficial for advanced tumors. In recent years, ELRA has been applied by more centers on larger scales, and the learning curve was set at 53 cases. Progresses in disease selection, surgical indications, individualized outflow reconstruction, or autograft implantation, management of co-morbidities (e.g., Budd-Chiari syndrome, caval and/or neighboring organ involvements, obstructive jaundice) propelled the development of the technique.

SUMMARY

This hybrid liver surgery will benefit for carefully selected patients presented with advanced benign diseases and well-differentiated malignancies.

Vascular reconstruction of segmental intestinal grafts using autologous internal iliac vessels

Background

The aim of this study was to assess whether the autologous internal iliac artery and vein could be used as an interpositional graft for vascular reconstruction in segmental intestinal allografts and autografts.

Methods

Thirty-four intestinal transplants (19 living-related allografts and 15 autografts) were conducted in our programs between January 2011 and January 2019. Patient characteristics, type of vascular reconstruction, and post-operative complications were reviewed.

Results

There were 20 males and 14 females with a median age of 35 years. Of 34 grafts, 22 (64.7%) (11 allografts and 11 autografts) were revascularized using the autologous internal iliac artery and vein for reconstruction. Vascular reconstruction on the back table took 21 ± 6 min to complete. Both total operative time and cold ischemia time tended to be longer in the vascular-reconstruction group than in the direct-anastomosis group (530 ± 226 vs 440 ± 116 and 159 ± 49 vs 125 ± 66 min, respectively), but these differences were not significant. The incidence of vascular thrombosis tended to be higher in the direct-anastomosis group than in the vascular-reconstruction group (16.7% vs 0%, P = 0.118). At a median follow-up of 36.9 months, no stenosis or pseudoaneurysms developed. In 19 allografts, acute rejection occurred in 4 (21.1%) and chronic rejection occurred in 1 (5.2%).

Conclusions

Our results indicate that the use of an autologous internal iliac interposition graft greatly facilitates intestinal graft implantation and minimizes the risk of vascular complications.

Artificial vascular graft migration into hollow viscus organs in patients who underwent right lobe living donor liver transplantation

BACKGROUND

To share our experience with hollow viscus migration of artificial vascular grafts (AVG) used for venous reconstruction of the right anterior sector in living donor liver transplantations (LDLT).

METHODS

Clinical, radiological, and endoscopic data of 13 right lobe LDLT patients (range: 26-67 years) with a diagnosis of postoperative AVG migration into adjacent hollow viscus were analyzed.

RESULTS

Biliary complications were detected in 12 patients. A median of four times endoscopic retrograde cholangiopancreatography (ERCP) procedures were performed in 11 patients prior to AVG migration diagnosis. A median of 2.5 times various percutaneous radiological interventional procedures were performed in eight patients prior to AVG migration diagnosis. The site of migration was the duodenum in eight patients, gastric antrum in four, and Roux limb in the remaining one patient. The migrated AVS were made of polytetrafluoroethylene (PTFE) in 10 patients and polyethylene terephthalate (Dacron) in three. The migrated AVGs were endoscopically removed in seven patients and surgically removed in six. Only one patient died due to sepsis unrelated to AVG migration.

CONCLUSION

AVG migration into the adjacent hollow viscus following right lobe LDLT is a rare and serious complication. Repetitive ERCP, interventional radiological procedures, infection related to biliary leakage, and thrombosis of AVGs are among the possible risk factors.

Is right lobe liver graft without main right hepatic vein suitable for living donor liver transplantation?

BACKGROUND

Since the first living donor liver transplantation (LDLT) was performed by Raia and colleagues in December 1988, LDLT has become the gold standard treatment in countries where cadaveric organ donation is not sufficient. Adequate hepatic venous outflow reconstruction in LDLT is essential to prevent graft congestion and its complications including graft loss. However, this can be complex and technically demanding especially in the presence of complex variations and congenital anomalies in the graft hepatic veins.

CASE SUMMARY

Herein, we aimed to present two cases who underwent successful right lobe LDLT using a right lobe liver graft with rudimentary or congenital absence of the right hepatic vein and describe the utility of a common large opening drainage model in such complex cases.

CONCLUSION

Thanks to this venous reconstruction model, none of the patients developed postoperative complications related to venous drainage. Our experience with venous drainage reconstruction models shows that congenital variations in the hepatic venous structure of living liver donors are not absolute contraindications for LDLT.

Eligibility of Circumferential Fence With the Autologous Peritoneal Patch for Venous Reconstruction in Right Lobe Living-Donor Liver Transplant: A Case Control Study

OBJECTIVES

: Our aim was to evaluate the eligibility of hepatic venous drainage technique using circumferential fence with peritoneal patch graft and saphenous vein graft in right lobe living-donor liver transplant.

MATERIALS AND METHODS

Between November 2007 and December 2017, our center performed 1413 rightlobe living-donor liver transplants. A circumferential fence was created using the peritoneal patch graft for venous drainage reconstruction in 31 of these patients. We compared data of these 31 patients with data of 62 patients who had circumferential fence created with cryopreserved homologous saphenous vein graft (1:2 ratio). Patients with anastomotic stenosis (n = 10) and without anastomotic stenosis (n = 69) were also compared.

RESULTS

No statistically significant differences were found between the peritoneal patch graft group and the saphenous vein graft group in terms of clinical parameters, circumferential fence diameter, and postoperative anastomotic stenosis (7.1% vs 26.1%; P = .056). Postoperative anastomotic stenosis developed in 10 patients. No statistically significant differences were found between patients with and without anastomotic stenosis in terms of clinical parameters except for diameter of circumferential fence (P = .001). Diameter of circumferential fence less than 18 mm in patients with and without anastomotic stenosis was shown in 80% and 34.6% of patients, respectively (P = .02). Stenosis-free survival in saphenous vein graft group was significantly better than in the peritoneal patch graft group (P = .023). Our correlation analyses showed a strong correlation between diameter of circumferential fence and the tenosis rate in patients (P = .001).

CONCLUSIONS

Autologous peritoneal patch graft can be used for creating circumferential fence for hepatic outflow in living-donor liver transplant patients if no better option is available. Despite high anastomotic stenosis rates, peritoneal fencing responded well to radiologic dilatation or stent applications and provided good long-term patency.

Analysis of Risk Factors Affecting the Development of Infection in Artificial Vascular Grafts Used for Reconstruction of Middle Hepatic Vein Tributaries in Living Donor Liver Transplantation

BACKGROUND

To analyze the risk factors affecting the development of infection in artificial vascular grafts (AVGs) used for reconstruction of middle hepatic vein (MHV) tributaries in living donor liver transplantation (LDLT).

METHODS

Between January 2009 and January 2018, 1253 right lobe LDLTs were performed at our Transplant Institute, and MHV tributaries of the 640 right lobe liver grafts were reconstructed with AVG. Reconstructed MHV tributaries were removed due to AVG infection in 25 of these patients (case group; n = 25). To determine risk factors for AVG infection, right lobe LDLT patients without AVG infections were selected as control group (n = 615). Both groups were compared about demographic parameter, transcystic catheter usage, bile leakage, type of biliary anastomosis (duct-to-duct, telescopic duct-to-duct), number of graft biliary duct (=1 versus >1), number of biliary anastomosis (=1 versus >1), AVG thrombosis, AVG types (Dacron versus polytetrafluoroethylene). Univariate analyses were used for comparison of different variables, and variables with P ≤ 0.20 were taken into logistic regression model.

RESULTS

Univariate analysis shows that statistically significant differences were found between groups regarding bile leakage (P < 0.001), graft thrombosis (P = 0.002), transcystic catheter (P = 0.049), and AVG types (P = 0.013). Variables with P ≤ 0.20 were taken into logistic regression model. Multivariate analysis shows that bile leakage (odds ratio, 13.3) and AVG thrombosis (odds ratio, 9.8) were determined as independent and strong risk factors for development of AVG infection.

CONCLUSIONS

This study revealed that bile leakage and graft thrombosis are independent and strong risk factors for infections of AVGs used for anterior sector drainage reconstruction.

Bio Mimicking of Extracellular Matrix

Biomaterials play a critical role in regenerative strategies such as stem cell-based therapies and tissue engineering, aiming to replace, remodel, regenerate, or support damaged tissues and organs. The design of appropriate three-dimensional (3D) scaffolds is crucial for generating bio-inspired replacement tissues. These scaffolds are primarily composed of degradable or non-degradable biomaterials and can be employed as cells, growth factors, or drug carriers. Naturally derived and synthetic biomaterials have been widely used for these purposes, but the ideal biomaterial remains to be found. Researchers from diversified fields have attempted to design and fabricate novel biomaterials, aiming to find novel theranostic approaches for tissue engineering and regenerative medicine. Since no single biomaterial has been found to possess all the necessary characteristics for an ideal performance, over the years scientists have tried to develop composite biomaterials that complement and combine the beneficial properties of multiple materials into a superior matrix. Herein, we highlight the structural features and performance of various biomaterials and their application in regenerative medicine and for enhanced tissue engineering approaches.