Outflow Reconstruction Using Cryopreserved Homologous Venous Grafts in Living Donor Liver Transplantation

Feasibility of venous cuff using an open round ligament or inferior mesenteric vein around the hepatic vein for a left lobe graft in living-donor liver transplantation

Living-donor liver transplantation (LDLT) is an established treatment for patients with end-stage liver disease or acute liver failure, and outflow reconstruction is considered one of the most vital techniques in LDLT. To date, many strategies have been reported to prevent outflow obstruction, which can be refractory to liver dysfunction and can cause life-threatening graft loss or mortality. In addition, in this era of laparoscopic hepatectomy in donor surgery, especially LDLT using a left liver graft, it has been predicted that cutting the hepatic vein with automatic linear staplers will lead to more outflow-related problems than with conventional open hepatectomy because of the short neck of the anastomosis orifice. We herein review 10 cases of venoplasty performed with a novel venous cuff system using a donor's round ligament around the hepatic vein in LDLT with a left lobe graft, which makes anastomosis of the hepatic vein sterically easy for postoperative venous patency.

Metallic Stents for Hepatic Venous Outflow Obstruction After Living-Donor Liver Transplantation and their Therapeutic Effects

BACKGROUND

Living-donor liver transplantation (LDLT) is established as a standard therapy for end-stage liver disease; however, vessel reconstruction is more demanding due to the short length and small size of the available structures compared with deceased-donor whole liver transplantation. Interventional radiology (IR) has become the first-line treatment for vascular complications after LDLT. Hepatic venous outflow obstruction (HVOO) is a life-threatening complication after LDLT. The aim of this study of 592 adult-to-adult LDLT cases was to investigate the safety and efficacy of stent implantation for HVOO after LDLT.

METHODS

Records of patients who developed HVOO requiring any treatment were collected with special reference to the metallic stent implantation. There were 232 left-side grafts and 360 right-side grafts. Sixteen cases developed HVOO after LDLT with an incidence rate of 2.7%, 5 with a left liver graft (2%), and 11 with a right-side graft (3%). The IR was attempted for 14 cases; among those, 8 cases were treated by stent implantation.

RESULTS

The technical success rate of the initial stent implantation was 100%. The pressure gradient at the stenotic site significantly improved from 12.2 (range, 10.9-20.4 cm H2O) to 3.9 cm H2O (range, 1.4-8.2 cm H2O; P = .03). The volume of the congested graft liver decreased significantly from 1448 (range, 788-2170 mL) to 1265 mL (range, 748-1665 mL; P = .01), and the serum albumin level improved significantly from 3.3 (range, 1.7-3.7 g/dL) to 3.7 g/dL (range, 2.9-4.1 g/dL; P = .02). No procedure-related complication was noted, and the long-term stent patency was 100%.

CONCLUSION

Metallic stent implantation for stenotic venous anastomosis after LDLT is a safe and effective treatment.

Technical challenges in LDLT - Overcoming small for size syndrome and venous outflow reconstruction

Living Donor Liver Transplantation (LDLT) emerged as an alternative treatment option for patients with end-stage liver disease waiting for an organ from a deceased donor. In addition to allowing for a faster access to transplantation, LDLT provides improved recipient outcomes when compared to deceased donor LT. However, it represents a more complex and demanding procedure for the transplant surgeon. In addition to a comprehensive preoperative donor assessment and stringent technical considerations during the donor hepatectomy to ensure upmost donor safety, the recipient procedure also comes with intrinsic challenges during LDLT. A proper approach during both procedures will result in favorable donor and recipient's outcomes. Hence, it is critical for the transplant surgeon to know how to overcome such technical challenges and avoid deleterious complications. One of the most feared complications following LDLT is small-for-size syndrome (SFSS). Although, surgical advances and deeper understanding of the pathophysiology behind SFSS has allowed for a safer implementation of LDLT, there is currently no consensus on the best strategy to prevent or manage this complication. Therefore, we aim to review current practices in technically challenging situations during LDLT, with a particular focus on management of small grafts and venous outflow reconstructions, as they possess one of the biggest technical challenges faced during LDLT.

Right Lobe Versus Left Lobe Living Donor Liver Transplantation: A Systematic Review and Meta-analysis of Donor and Recipient Outcomes

BACKGROUND

Living donor liver transplantation (LDLT) is an established treatment for advanced liver disease. Whether right lobe (RL) or left lobe (LL) LDLT provides the best outcomes for donors and recipients remains contentious.

METHODS

MedLine, Embase, PubMed, and Cochrane Central were searched to identify studies comparing RL- and LL-LDLT and reporting donor and/or recipient outcomes. Effect sizes were pooled using random-effect meta-analysis. Meta-regressions were used to explore heterogeneity.

RESULTS

Sixty-seven studies were included. RL donors were more likely to experience major complications (relative risk [RR] = 1.63; 95% confidence interval [CI] = 1.30-2.05; I2 = 19%) than LL donors; however, no difference was observed in the risk of any biliary complication (RR = 1.41; 95% CI = 0.91-2.20; I2 = 59%), bile leaks (RR = 1.56; 95% CI = 0.97-2.51; I2 = 52%), biliary strictures (RR = 0.99; 95% CI = 0.43-1.88; I2 = 27%), or postoperative death (RR = 0.51; 95% CI = 0.25-1.05; I2 = 0%). Among recipients, the incidence of major complications (RR = 0.85; 95% CI = 0.68-1.06; I2 = 21%), biliary complications (RR = 1.10; 95% CI = 0.91-1.33; I2 = 8%), and vascular complications (RR = 0.79; 95% CI = 0.44-1.43; I2 = 0%) was similar. Although the rate of small for size syndrome (RR = 0.47; 95% CI = 0.30-0.74; I2 = 0%) and postoperative deaths (RR = 0.62; 95% CI = 0.44-0.87; I2 = 0%) was lower among RL-LDLT recipients, no differences were observed in long-term graft (hazard ratio = 0.87; 95% CI = 0.55-1.38; I2 = 74%) and overall survival (hazard ratio = 0.86; 95% CI = 0.60-1.22; I2 = 44%).

CONCLUSIONS

LL donors experience fewer complications than RL donors, and LL-LDLT recipients had similar outcomes to RL-LDLT recipients. These findings suggest that LL-LDLT offers the best outcomes for living donors and similar outcomes for recipients when measures are taken to prevent small for size syndrome.

Back table Preparation of the Right Lobe Live Donor Liver Allograft: A Crucial Part of the Adult Live Donor Liver Transplant Procedure

INTRODUCTION

We aimed to describe our procedure for vascular reconstruction and back table bench preparation for the right lobe live donor allograft. Live donor liver transplantation (LDLT) remains an important option for the expansion of the donor pool. The procedure has been widely used, and its success is dependent on a technically perfect operation with appropriate inflow and outflow of the allograft. Adequate preparation of the right lobe (RL) allograft prior to implantation remains a vital part of the procedure.

METHODS

Our technique of back table vascular reconstruction of the RL allograft has been performed using a hepatic vein patch venoplasty, inferior hepatic vein inclusion, portal vein reconstruction, and segment V and VIII reconstruction for all of our LDLTs.

RESULTS

Between March 2009 and January 2020, 321 consecutive adult LDLTs were performed and underwent back table reconstruction with the techniques described. During that time period, no patients had hepatic insufficiency. There was a single thrombosis of a superior mesenteric vein (SMV) to PV jump conduit.

CONCLUSIONS

Our technique of back table reconstruction of the LDLT right lobe graft remains a crucial part of the operative procedure. Our experience with RL grafts without middle hepatic vein (MHV) and our systematic approach for inflow and outflow reconstruction has yielded excellent results with no technical outflow issues and minimal inflow complications.

Clinical Significance of Spontaneous Portosystemic Shunts in Living Donor Liver Transplantation

Spontaneous portosystemic shunts (SPSS) are commonly observed in patients undergoing living donor liver transplantation (LDLT); however, their impact on the outcome after transplantation is unclear. We aimed to assess the type, size, and the effects of SPSS on outcomes after LDLT. A total of 339 LDLT recipients in a single institution were included. The type and diameter of the SPSS (splenorenal shunt [SRS], oesogastric shunt, and umbilical shunt) were retrospectively analyzed. A large shunt was defined as having a diameter ≤7 mm. No portal flow modulation was attempted over time. Portal complications were defined as stenosis, thrombosis, or hepatofugal flow requiring any treatment after transplantation. There were 202 (59.0%) patients who exhibited at least 1 large SPSS. Neither the size nor type of SPSS was associated with mortality, morbidity, or liver function recovery. However, the incidence of portal complications was significantly higher in patients with a large SRS (8.6% versus 2.9%; P = 0.04). Multivariate analysis of portal complications revealed 2 independent predictors: pre-LT portal vein thrombosis (PVT) and SRS size. The observed risk among recipients with pre-LT PVT was 8.3% when the SRS was ≤7 mm, but increased to 38.5% when the SRS was >15 mm. The present study suggests that large SPSS do not negatively affect the outcomes after LDLT. However, a large SRS is associated with a higher risk of portal complications, particularly in recipients with pre-LT PVT, for whom intraoperative intervention for SRS should be considered. Otherwise, a conservative approach to SPSS during LDLT seems reasonable.

Feasibility of bile duct as venous graft for venous reconstruction in pancreatic surgery: An animal experimental study

OBJECTIVE

Pancreatic cancer is a kind of high malignant tumor with a poor prognosis. The aim is to determine whether the dilated bile duct can be used to reconstruct the vessels.

METHODS

An animal model of jugular vein and portal vein reconstruction was established using the bile duct. A total of 20 landrace pigs were selected to undergo jugular vein reconstruction or portal vein reconstruction using the bile duct as a patch or bridge. The patency was evaluated by color Doppler, the reconstructed segments were removed and examined macroscopically and histologically at specified intervals, and the results were compared with synthetic vessels (IMPRA straight, 10s03-19).

RESULTS

The lumen was patent, although a low level thrombosis was observed when jugular or portal vein patching was used. For bridging, stenosis of the lumen was observed, and necrosis appeared when the bile duct was used for bridging, indicating that it is feasible to reconstruct the jugular vein and portal vein with a bile duct patch. However, the bridge was not feasible possibly due to loss of blood supply, and consequent necrosis and fibrosis.

CONCLUSION

The bile duct is technically feasible, but the outcomes are unsatisfactory.

Reconstruction of Middle Hepatic Vein Tributaries With Artificial Vascular Grafts in Living Donor Liver Transplant Using Right Lobe Grafts: A Case Series

BACKGROUND

Congestion of the anterior section of the grafted liver might be a problem when performing living donor liver transplant using a right lobe graft without middle hepatic vein (MHV). This can be prevented by MHV tributary reconstruction. We report our procedure and results of reconstructing MHV tributaries using artificial vascular grafts (AVGs).

METHODS

We consider venous reconstruction when the estimated territory of each MHV tributary of the transplanted liver is more than 100 mL. For tributaries distant from the stump of the right hepatic vein of the graft, we use heparin-bonded AVGs made of expanded polytetrafluoroethylene with circular rings as the interposition graft between the MHV tributary and the inferior vena cava. During donor surgery, the suturing margin of the MHV tributary is secured before cutting, and it is anastomosed to the AVG during back-bench surgery. After restoration of portal flow in the recipient, we anastomose the AVG at a new position on the inferior vena cava.

RESULTS

The above procedure was performed for 4 cases. The estimated drainage territory of the vein that was reconstructed using the AVG ranged from 104 to 180 mL. The AVG patency was achieved for about 2 months in all cases. In terms of morbidity, biloma and pancreatic fistula were observed in 2 cases, although removal of the AVG was not required postoperatively in any of the cases.

CONCLUSION

The heparin-bonded expanded polytetrafluoroethylene AVG with circular rings is a feasible option for MHV tributary reconstruction in living donor liver transplant using right liver lobe grafts without MHVs.

Impact of the Inferior Right Hepatic Veins on Right Liver Lobe Regeneration in Living-Donor Liver Transplant: 3-Dimensional Computed Tomography Scan Analyses in Donors and Recipients

OBJECTIVES

The presence of an inferior right hepatic vein significantly modifies the outflow pattern of the right liver and may have an impact on graft regeneration.

MATERIALS AND METHODS

Study patients were donors and recipients with 3-dimensional computed tomography scan simulation. We studied the physiologic impact of the inferior right hepatic veins on right liver regeneration in donors of left lobe grafts (step1; n = 60 patients) and the efficacy of a inferior right hepatic vein reconstruction policy based on a vessel caliber > 5 mm criteria in recipients of right liver grafts (step 2; n = 38 patients).

RESULTS

In step 1, the regeneration rate at 1 month was comparable between future liver remnants with inferior right hepatic vein (regeneration rate of 28.3%) and without inferior right hepatic vein (regeneration rate of 30.2%). In step 2, at 3 months after living-donor liver transplant, we observed no significant differences in regeneration rates among grafts anatomically without an inferior right hepatic vein (regeneration rate of 60.7%), grafts with an inferior right hepatic vein but no reconstruction (regeneration rate of 64.9%), and grafts with an inferior right hepatic vein and its reconstruction (regeneration rate of 68.1%). Within the latter subgroup, grafts with a dominant inferior right hepatic vein showed a greater regeneration of the anterior sector with inversion of the anterior-to-posterior sector regeneration ratio compared with right hepatic vein-dominant grafts (inferior right hepatic vein-dominant vs right hepatic vein-dominant showed anterior sector regeneration rates of 85.7% vs 52.1%; P = .02; anterior/posterior sector regeneration ratio was 2.3 vs 0.6, respectively; P = .04).

CONCLUSIONS

The reconstruction policy for inferior right hepatic vein with caliber > 5 mm is effective but should be implemented with computed tomography scan simulation. Right lobe grafts with a dominant inferior right hepatic vein are at higher risk of impaired regeneration due to expected large volumes of hepatic venous congestion if the middle hepatic veins tributaries or the inferior right hepatic veins are not reconstructed and an increased rate of right hepatic vein complications.

Novel use of percutaneous thrombosuction to rescue the early thrombosis of the conduit vein graft after living donor liver transplantation

A 54-year-old woman with liver cirrhosis and hepatocellular carcinoma received a living donor liver transplant. Thrombosis of the segmental hepatic vein occurred on postoperative day 7. We undertook percutaneous catheter thrombosuction under local anesthesia to extract the thrombus successfully without re-exploration. Thrombosuction has been used for thrombosis of the cardiovascular system, limbs, and brain. We first used it in hepatic venous thrombus after liver transplantation. This procedure is simple, less invasive, feasible, safe, repeatable, and effective.

The choice of cryopreservation method affects immune compatibility of human cardiovascular matrices

Conventional frozen cryopreservation (CFC) is currently the gold standard for cardiovascular allograft preservation. However, inflammation and structural deterioration limit transplant durability. Ice-free cryopreservation (IFC) already demonstrated matrix structure preservation combined with attenuated immune responses. In this study, we aim to explore the mechanisms of this diminished immunogenicity in vitro. First, we characterized factors released by human aortic tissue after CFC and IFC. Secondly, we analyzed co-cultures with human peripheral blood mononuclear cells, purified monocytes, T cells and monocyte-derived macrophages to examine functional immune effects triggered by the tissue or released cues. IFC tissue exhibited significantly lower metabolic activity and release of pro-inflammatory cytokines than CFC tissue, but surprisingly, more active transforming growth factor β. Due to reduced cytokine release by IFC tissue, less monocyte and T cell migration was detected in a chemotaxis system. Moreover, only cues from CFC tissue but not from IFC tissue amplified αCD3 triggered T cell proliferation. In a specifically designed macrophage-tissue assay, we could show that macrophages did not upregulate M1 polarization markers (CD80 or HLA-DR) on either tissue type. In conclusion, IFC selectively modulates tissue characteristics and thereby attenuates immune cell attraction and activation. Therefore, IFC treatment creates improved opportunities for cardiovascular graft preservation.