Storage of allogeneic vascular grafts: experience from a high-volume liver transplant institute

Fuzi Polysaccharide Isolated from Aconitum Carmichaeli Protects Against Liquid Nitrogen Cryopreservation-Induced Damage in Rat Abdominal Aorta by Enhancing Autophagy

BACKGROUND

To investigate the potential protective mechanisms of aconite polysaccharide (fuzi polysaccharide [FZPS-1]) during cryopreservation, with a particular emphasis on morphological changes in autophagy in rat abdominal aorta.

METHODS

Thirty-six male standard deviation rats were divided into the control group, the cryopreserved model group, and the FZPS-1 intervention group treated with different concentrations of FZPS-1. The structural changes of the abdominal aortic wall were assessed via Masson staining, while cytolysosomes were identified using transmission electron microscope (TEM). The expression of Beclin-1, microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, and P62 was detected by immunohistochemistry and western blot separately. Bcl-2 and Bax messenger RNA (mRNA) expression was measured by RT-qPCR.

RESULTS

Compared with the control group, the abdominal aortic wall in the model group was severely damaged. Contrarily, FZPS-1 10 mg/mL and 20 mg/mL groups had relatively normal structure of the blood vessel wall, higher cytolysosome counts, and increased Beclin-1 and LC3-II expression compared with the model group (all P < 0.05); P62 expression also increased in the FZPS-1 20 mg/mL group (P < 0.05). Compared with the control group, the mRNA expression of Bcl-2 in the cryopreservation model group was reduced (P < 0.05), while Bax was increased (P < 0.05). Compared with the cryopreservation model group, the mRNA expression of Bcl-2 was upregulated, while Bax was downregulated in the farnesyl pyrophosphate synthase 10 mg/L group (P < 0.05).

CONCLUSION

During liquid nitrogen cryopreservation, autophagy is inhibited in the rat abdominal aorta, and the blood vessel wall structure is damaged. FZPS-1, as a cryoprotectant, can enhance autophagy and mitigate blood vessel wall damage in the rat abdominal aorta.

The Influence of Textile Structure Characteristics on the Performance of Artificial Blood Vessels

Cardiovascular disease is a major threat to human health worldwide, and vascular transplantation surgery is a treatment method for this disease. Often, autologous blood vessels cannot meet the needs of surgery. However, allogeneic blood vessels have limited availability or may cause rejection reactions. Therefore, the development of biocompatible artificial blood vessels is needed to solve the problem of donor shortage. Tubular fabrics prepared by textile structures have flexible compliance, which cannot be matched by other structural blood vessels. Therefore, biomedical artificial blood vessels have been widely studied in recent decades up to the present. This article focuses on reviewing four textile methods used, at present, in the manufacture of artificial blood vessels: knitting, weaving, braiding, and electrospinning. The article mainly introduces the particular effects of different structural characteristics possessed by various textile methods on the production of artificial blood vessels, such as compliance, mechanical properties, and pore size. It was concluded that woven blood vessels possess superior mechanical properties and dimensional stability, while the knitted fabrication method facilitates excellent compliance, elasticity, and porosity of blood vessels. Additionally, the study prominently showcases the ease of rebound and compression of braided tubes, as well as the significant biological benefits of electrospinning. Moreover, moderate porosity and good mechanical strength can be achieved by changing the original structural parameters; increasing the floating warp, enlarging the braiding angle, and reducing the fiber fineness and diameter can achieve greater compliance. Furthermore, physical, chemical, or biological methods can be used to further improve the biocompatibility, antibacterial, anti-inflammatory, and endothelialization of blood vessels, thereby improving their functionality. The aim is to provide some guidance for the further development of artificial blood vessels.

Design and characterization of small-diameter tissue-engineered blood vessels constructed by electrospun polyurethane-core and gelatin-shell coaxial fiber

Substitution or bypass is the most effective treatment for vascular occlusive diseases.The demand for artificial blood vessels has seen an unprecedented rise due to the limited supply of autologous blood vessels. Tissue engineering is the best approach to provide artificial blood vessels. In this study, a new type of small-diameter artificial blood vessel with good mechanical and biological properties was designed by using electrospinning coaxial fibers. Four groups of coaxial fibers vascular membranes having polyurethane/gelatin core-shell structure were cross-linked by the EDC-NHS system and characterized. The core-shell structure of the coaxial vascular fibers was observed by transmission electron microscope. After the crosslinking, the stress and elastic modulus increased and the elongation decreased, burst pressure of 0.11 group reached the maximum (2844.55 ± 272.65 mmHg) after cross-linking, which acted as the experimental group. Masson staining identified blue-stained ring or elliptical gelatin ingredients in the vascular wall. The cell number in the vascular wall of the coaxial group was found in muscle embedding experiment significantly higher than that of the non-coaxial group at all time points(p < 0.001). Our results showed that the coaxial vascular graft with the ratio of 0.2:0.11 had better mechanical properties (burst pressure reached 2844.55 ± 272.65 mmHg); Meanwhile its biological properties were also outstanding, which was beneficial to cell entry and offered good vascular remodeling performance.Polyurethane (PU); Gelatin (Gel); Polycaprolactone (PCL); polylactic acid (PLA);1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC); N-Hydroxy succinimide (NHS); 4-Morpholine-ethane-sulfonic (MES); phosphate buffered saline (PBS); fetal calf serum (FCS); Minimum Essential Medium (MEM); Dimethyl sulfoxide (DMSO); hematoxylin-eosin (HE).

Investigation of a method for long-term preservation of the vascular allograft

BACKGROUND/OBJECTIVE

During multiple organ procurement, blood vessels are routinely retrieved and stored in University of Wisconsin solution and then discarded after two weeks, if not used at organ transplantation owing to lack of a method for long-term preservation. Therefore, the aim of this study is to investigate a method for long-term preservation of vascular allografts in ethanol.

METHODS

Aorta and vena cava allografts were retrieved and stored in 75% ethanol solution for 12 months at 4°C. Four pigs were divided into two groups. A segment of aorta was excised and replaced by insertion of preserved aorta graft (Group A) or vena cava graft (Group V). The pigs were observed for six weeks. A laparotomy was performed and the vascular graft was harvested for histopathology followed by euthanasia at the end of study.

RESULTS

Three pigs recovered uneventfully, while one pig died from venous graft rupture in the third week after surgery. There was no aneurysmal formation or thrombosis in the grafts. Some calcification was seen over aorta allograft. On histopathology, the elastic pattern was almost normal, although the endothelial cells degenerated after preservation. After implantation, the formation of the endothelium cell-like layer was seen in both aorta and vena cava allografts.

CONCLUSION

Vascular allografts were functional after preservation for 12 months. The vena cava grafts had much less wall calcification than the aorta grafts. Further studies are necessary to investigate vascular graft remodelling with a longer observation period after implantation.

Living-donor liver transplantation in Budd-Chiari syndrome with inferior vena cava complete thrombosis: A case report and review of the literature

BACKGROUND

Budd-Chiari syndrome (BCS) is a challenging indication for liver transplantation (LT) due to a combination of massive liver, increased bleeding, retroperitoneal fibrosis and frequently presents with stenosis of the inferior vena cava (IVC). Occasionally, it may be totally thrombosed, increasing the complexity of the procedure, as it should also be resected. The challenge is even greater when performing living-donor LT as the graft does not contain the retrohepatic IVC; thus, it may be necessary to reconstruct it.

CASE SUMMARY

A 35-year-old male patient with liver cirrhosis due to BCS and hepatocellular carcinoma beyond the Milan criteria underwent living-donor LT with IVC reconstruction. It was necessary to remove the IVC as its retrohepatic portion was completely thrombosed, up to almost the right atrium. A right-lobe graft was retrieved from his sister, with outflow reconstruction including the right hepatic vein and the branches of segment V and VIII to the middle hepatic vein. Owing to massive subcutaneous collaterals in the abdominal wall, venovenous bypass was implemented before incising the skin. The right atrium was reached via a transdiaphragramatic approach. Hepatectomy was performed en bloc with the retrohepatic vena cava. It was reconstructed with an infra-hepatic vena cava graft obtained from a deceased donor. The patient remains well on outpatient clinic follow-up 25 mo after the procedure, under an anticoagulation protocol with warfarin.

CONCLUSION

Living-donor LT in BCS with IVC thrombosis is feasible using a meticulous surgical technique and tailored strategies.

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.

Usability of Inferior Vena Cava Interposition Graft During Living Donor Liver Transplantation: Is This Approach Always Necessary?

PURPOSE

To share the outcome of caval reconstruction technique in patients who underwent living donor liver transplantation (LDLT) with inferior vena cava (IVC) interposition grafting.

METHODS

Between January 2009 and December 2018, an artificial or homologous interposition vascular graft was used for the continuity of resected native (IVC) due to various reasons in 29 of 1740 patients who underwent LDLT at our institute. Demographic, clinical, and radiological data were prospectively collected and retrospectively analyzed.

RESULTS

Sixteen female and 13 male patients ranging 6-67 years of age were included. Right, left, and left lobe lateral segments were used in 22, 5, and 2 patients, respectively. The three leading LDLT indications were primary or idiopathic Budd-Chiari syndrome (BCS) (n = 12), alveolar echinococcosis (n = 7), and secondary BCS (n = 5). The three leading indications for IVC interposition grafting were thrombosis, dense fibrosis, and IVC invasion caused by tumor or echinococcosis. Homologous IVC graft was used in 17, homologous aortic graft in 7, and Dacron graft in 5 patients. Throughout the follow-up period, ascites ± pleural effusion and elevated liver enzymes were detected in 12 and 4 patients, respectively. Stenosis and/or thrombosis requiring one or more procedures such as 1-6 sessions balloon angioplasty, stent, and thrombus aspiration were observed in half of the patients.

CONCLUSION

Retrohepatic IVC damages are not a contraindication for LDLT. The presence or absence of venous collateral circulation is an important indicator of the need for IVC interposition graft use.

Living-donor liver transplantation with inferior vena cava replacement in an infant recipient with advanced hepatoblastoma

Replacement of the inferior vena cava (IVC) after concurrent resection of hepatoblastoma-containing liver and retrohepatic IVC is regarded as a feasible option for pediatric living-donor liver transplantation (LDLT). This technique makes the extent of resection of LDLT comparable to that of deceased-donor liver transplantation (DDLT). We present one case of pediatric LDLT with IVC homograft replacement for advanced hepatoblastoma. The patient was a 10-kg 18-month-old girl suffering from large multiple hepatoblastomas, which were partially regressed by neoadjuvant chemotherapy. Because the tumors had invaded the retrohepatic IVC, there was a high risk of residual tumor cells at the IVC if it was preserved. Thus, we decided to replace the IVC during the LDLT operation. After a cold-stored fresh iliac vein homograft was prepared, we performed LDLT using her mother's left lateral section liver graft. A 4-cm-long common iliac vein homograft was attached to the liver graft at the back table. The left lateral-section graft with IVC attachment was implanted using the standard procedures like those of DDLT. We also did portal vein graft interposition. The patient recovered uneventfully and has been undergoing scheduled adjuvant chemotherapy to date. This is our second case of IVC homograft replacement for pediatric LDLT. In pediatric recipients, various vein homografts, such as iliac vein, IVC, and other large veins, can be used depending on the body size of the recipient and availability of vein homografts.

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.

Living Donor Liver Transplantation With Vena Cava Replacement

OBJECTIVES

This study sought to evaluate the indications, techniques, and results of inferior vena cava (IVC) replacement at living donor liver transplantation (LDLT).

MATERIALS AND METHODS

We performed 821 LDLTs and 11 (1.3%) patients required concomitant IVC replacement. We analyzed the indications, replacement materials, and outcomes.

RESULTS

Right, left, and left lateral liver lobes were transplanted in 7, 2, and 2 patients, respectively. The indications for IVC replacement were thrombosis/fibrosis in 7 patients (Budd-Chiari 4, hereditary tyrosinemia 1, congenital hepatic fibrosis 1, cryptogenic 1), involvement with mass in 3 patients (Echinococcus alveolaris 2, hepatoblastoma 1) and iatrogenic narrowing at IVC in 1 patient. Cryopreserved grafts (aorta n = 5, IVC n = 4, iliac vein n = 1) or synthetic graft (n = 1) were used for replacements. In 1 patient, hepatic outflow obstruction developed at 39 days and was treated successfully by interventional radiology. There was only 1 hospital mortality (8.9%) that was unrelated to caval replacement (subarachnoid hemorrhage). Of the remaining patients, the caval grafts were patent after a mean 7.7 months of follow-up (range 1 to 17 months).

CONCLUSIONS

Although rare, IVC replacement can be necessary at LDLT. Budd-Chiari and E. alveolaris are the main underlying diseases for replacement requirements. Caval replacement with cryopreserved vascular grafts can provide successful short-term and long-term patency.

Histopathologic Findings of Cholecystectomy Specimens in Patients Who Underwent Donor Hepatectomy for Living Donor Liver Transplantation

BACKGROUND

The aim of this study was to discuss the macroscopic and microscopic properties of gallbladder specimens obtained from living liver donors.

METHODS

The study retrospectively analyzed the clinical and histopathological data of 1088 donors who underwent living donor hepatectomy between March 2005 and September 2014 at Inonu University Faculty of Medicine, Liver Transplantation Center. Age, sex, macroscopic, and microscopic properties of the gallbladder (bladder length, diameter, content, and histopathological properties) were recorded by 2 researchers.

RESULTS

A total of 1009 donors aged 17 to 66 years (31.1 ± 9.5) met the inclusion criteria, whereas 79 donors were excluded due to missing data. In total, 587 donors were male (30.5 ± 9.1 years [16-63 years]) and 422 were female (31.8 ± 9.8 years [18-66 years]). Preoperative tests revealed Gilbert syndrome in 3 subjects, whereas other donors' biochemical tests were within normal ranges. The macroscopic examination of gallbladders revealed mean gallbladder wall thickness, length, and width of 1.82 ± 0.8 mm (1-10 mm), 72 ± 11.4 mm (40-120 mm), and 52.5 ± 14 mm (15-90 mm), respectively. The microscopic gallbladder examination showed that 740 donors had a normal gallbladder, 193 had chronic cholecystitis (1 donor had antral metaplasia and 1 had intestinal metaplasia), 40 had cholesterolosis (1 donor had both tubular adenoma and intestinal metaplasia), 15 had minimal chronic cholecystitis (1 donor had pyloric metaplasia), 14 had cholelithiasis, 2 had adenomyosis, 2 had muscular hypertrophy, 1 had papillary hyperplasia, 1 had microdiverticulitis, and 1 had mucosal lymphatic ectasia.

CONCLUSION

The results of this study reflect the actual gallbladder pathologies that can be detected in healthy people. Clearer conclusions can be reached about the epidemiological data on gallbladder as the number of living liver donors increases in the future.

"V-Plasty" technique using dual synthetic vascular grafts to reconstruct outflow channel in living donor liver transplantation

BACKGROUND

The reconstruction of outflow is a crucial step in living donor liver transplantation. This study describes a suitable technique that uses synthetic vascular conduits in presence of multiple draining veins of right lobe of liver and the outcome of the recipients to evaluate safety of using multiple synthetic grafts.

METHODS

From March 2011 to September 2014, 325 patients underwent right lobe living donor liver transplantation. Expanded polytetra-fluoroethylene (ePTFE) grafts were used in total 155 of the liver allografts. Among these, 16 liver grafts required dual ePTFE grafts to reconstruct the outflow due to presence of multiple hepatic veins.

RESULTS

The mean diameters for venous branches of segment 5 (V5) and 8 (V8) were 5 mm (range, 4-8 mm) and 7 mm (range, 5-9 mm). The mean diameter of inferior right hepatic veins was 8 mm (7-10 mm). All the recipients who received the right liver with dual ePTFE grafts showed satisfactory inflow and outflow immediately after reconstruction as measured by Doppler flowmetry. Postoperative ultrasonographic studies showed no disturbances in outflow. Protocol dynamic computed tomography performed in the second postoperative month showed 100% patency rates of the artificial grafts. At median follow-up of 24 months graft survival was achieved in 88%, whereas the patency rates of the ePTFE grafts were 100%.

CONCLUSION

The use of "V-Plasty" technique using dual artificial vascular grafts is a safe and feasible technique in the presence of various allograft venous anomalies & ensures a single venous channel for outflow reconstruction. Our study also suggests that ePTFE graft may be a useful interposition material without serious complications.

Living related donor liver transplantation with atrio-caval anastomosis of inferior vena cava graft stored in deep-freeze for budd-Chiari syndrome

We have previously reported our experience in inferior vena cava resection and reconstruction techniques during liver transplantation for Budd-Chiari syndrome. Herein, we present on a case that demonstrates the importance of experience in complex vascular reconstruction techniques for living donor liver transplantation. A 15-year-old boy was scheduled for living donor liver transplantation for Budd-Chiari syndrome. Venous occlusion was extended up to the right atrial orifice of the supra-hepatic vena cava. Retro- and supra-hepatic segments of the vena cava was resected. Inferior vena cava graft stored in deep-freeze was available. Venous reconstruction was performed with end-to-end atrio-caval anastomosis. Surgical treatment was completed with the implantation of the right liver lobe donated by the patient's mother. Post-surgical course was uneventful.

Novel rescue procedure for inferior vena cava reconstruction in living-donor liver transplantation using a vascular graft recovered 25 h after donors' circulatory death and systematic review

Liver transplantation is a lifesaving treatment for patients suffering from end-stage liver disease. Rarely, acute congestion of the inferior vena cava (IVC) is being encountered because of tumor compression. MELD allocation does not reflect severity of this condition because of lack of organ failure. Herein, a patient is being presented undergoing urgent living-donor liver transplantation (LDLT) with IVC reconstruction for a fast-growing hepatic epithelioid hemangioendothelioma (HEH). IVC reconstruction using a venous graft recovered from a 25-h after circulatory-death prior transplantation became necessary to compensate severe venous congestion. Additionally, a systematic review of the literature searching MEDLINE/PubMed was performed. Protocol and eligibility criteria were specified in advance and registered at the PROSPERO registry (CRD42013004827). Published literature of IVC reconstruction in LDLT was selected. Two reports describing IVC reconstruction with cryopreserved IVC grafts and one IVC reconstruction using a deceased after-circulatory-death-donor IVC graft were included. Follow-up was at 12 and 13 months, respectively. Regarding the graft recovery in the setting of living-related donation, this graft remained patent during the nine-month follow-up period. This is the first report on the use of a venous graft from a circulatory-death-donor, not eligible for whole organ recovery. We demonstrate in this study the feasibility of using a size and blood-group-compatible IVC graft from a cold-stored donor, which can solve the problem of urgent IVC reconstruction in patients undergoing LDLT.