Middle Hepatic Vein Tributaries Research Articles

Resection and reconstruction of the largest abdominal vein system (the inferior vena cava, hepatic, and portal vein): a narrative review.

As tumors invade major abdominal veins, surgical procedures are transformed from simple and basic to complicated and challenging. In this narrative review, we focus on what is currently known and not known regarding the technical aspects of major abdominal venous resection and its reconstruction, patency, and oncologic benefit in a cross-cutting perspective. A systematic literature search was performed in PubMed and Semantic Scholar from inception up to October 18, 2023. We reviewed 106 papers by title, abstract, and full text regarding resection or reconstruction of the inferior vena cava, hepatic vein confluence, portal vein (PV), and middle hepatic vein (MHV) tributaries in living donor liver transplantation (LDLT) in a cross-cutting perspective. The oncologic benefit of aggressive hepatic vein resection with suitable reconstruction against adenocarcinoma remains unclear, and further studies are required to clarify this point. A superior mesenteric/PV resection is now a universal, indispensable, and effective procedure for pancreatic ductal adenocarcinoma. Although many case series using tailor-made autologous venous grafts have been reported, not only size mismatch but also additional surgical incisions and a longer operation time remain obstacles for venous reconstruction. The use of autologous alternative tissue remains only an alternative procedure because the patency rate of customized tubular conduit type to interpose or replace the resected vein is not known. Unlike arterial replacement, venous replacement using synthetic vascular grafts is still rarely reported and there are several inherent limitations except for reconstruction of tributaries of MHV in LDLT. Various approaches to abdominal vein resection and replacement or reconstruction are technically feasible with satisfactory results. Synthetic vascular grafts may be appropriate but have a certain rate of complications.

Venous reconstruction using a round ligament-covered prosthetic vascular graft in right‑lobe living‑donor liver transplantation: a technical report.

To evaluate the short term-outcomes of venous reconstruction using a round ligament-covered prosthetic vascular graft and assess its effectiveness in the prevention of prosthetic vascular graft migration in right‑lobe living donor liver transplantation (LDLT). Thirty patients underwent reconstruction of the middle hepatic vein (MHV) tributaries during right lobe LDLT between January, 2021 and October, 2022. These patients were divided into the autologous vascular graft group (A group, n = 24) and the round ligament-covered prosthetic vascular graft group (RP group, n = 6). The computed tomography (CT) density ratio of the drainage area in the posterior segment of patent grafts was significantly higher in the RP group than in the A group (0.91 vs. 1.06, p = 0.0025). However, the patency rates of reconstructed MHV tributaries in the A and RP groups were 61% and 67%, respectively, with no significant difference between the groups (p = 0.72). Prosthetic vascular graft migration did not occur in the RP group. Venous reconstruction using round ligament-covered prosthetic vascular grafts is a feasible and simple method to prevent prosthetic vascular graft migration in right-lobe LDLT.

Innovative Technique Avoiding Bleeding After Reperfusion in Living Donor Liver Transplant Using a Modified Right Lobe Graft

Living donor liver transplant (LDLT) is a valuable therapeutic option for overcoming the deceased donor shortage. Modified right lobe graft (MRLG) keeps the middle hepatic vein (MHV) trunk with the remnant liver to improve donor safety. Hemostasis in the MHV tributary reconstruction can be tricky; surgical stitches and energy coagulation are ineffective. Fibrin glues are excellent vascular sealants but are poor in maintaining hemostasis in an active hemorrhage or preventing resection surface-related complications after liver resection. We propose applying fibrin sealant during back table graft preparation to seal the hepatic edge and MHV reconstruction to avoid bleeding after graft revascularization. Our retrospective cohort study included all adult patients undergoing LDLT between August 2017 and December 2021. During the back table procedure, we performed the reconstruction of the inferior right hepatic vein and/or MHV tributaries from segment 5 (V5) and segment 8 (V8) using a vein harvested from a nonrelated deceased donor. Before initiating the hepatic graft implantation, we applied fibrin sealant in the resected parenchyma, especially in the V5 and V8 anastomosis, to seal the hepatic edge and hepatic vein reconstruction. No bleeding was identified in the hepatic edge, and blood product transfusion was unnecessary for any recipients after reperfusion. In LDLT using MRLG with MHV reconstruction, the fibrin sealant, when applied on the raw hepatic surface, and vascular reconstruction during back table graft preparation avoided bleeding after graft revascularization.

Importance of reconstruction of middle hepatic vein tributaries of right-lobe grafts in living donor liver transplantation: demonstration of the reconstruction technique.

The aim of the present study on living donor liver transplantation (LDLT) using a right-lobe graft without the middle hepatic vein (MHV) was to investigate the clinical impact of MHV tributary reconstruction using our criteria and techniques. The medical records of 40 patients who underwent adult LDLT using a right-lobe graft without the MHV between April 2008 and December 2020 were retrospectively reviewed. In this cohort, the criterion for MHV tributary reconstruction was estimated drainage volume of each MHV tributary greater than 100mL. The drainage vein of segment 8(V8) was reconstructed as the common orifice of the right hepatic vein and V8 using a venous patch graft, and that of segment 5 was reconstructed using artificial vascular grafts. The outcomes were compared between the groups with and without MHV tributary reconstruction. Factors associated with postoperative massive ascites were also investigated. Twenty patients underwent MHV tributary reconstruction. There were no significant differences in the amount of postoperative ascites, Clavien-Dindo classification ≥ III postoperative complications, and 90-day in-hospital mortality between the groups (P = 0.678, P = 1.000, and P = 0.244, respectively). On multivariate analyses, a low-estimated functional graft-to-recipient weight ratio, which was calculated using estimated graft volume minus the territory of MHV tributaries that was not reconstructed, was identified as an independent predictor of postoperative massive ascites (odds ratio, 40.479; 95% confidence interval, 3.823-428.622). The present study suggests that selective MHV tributary reconstruction might be useful for achieving successful graft function.

Anatomy of the Middle Hepatic Vein Tributaries to Promote Safer Hepatic Vein-Guided Liver Resection

BackgroundIn laparoscopic anatomic liver resection, an increasingly common procedure, the hepatic vein-guided approach is widely used although the hepatic vein tributaries can be a major source of bleeding in the event of inadvertent injury. This report describes the anatomy of the middle hepatic vein (MHV) including its tributaries based on reconstructed three-dimensional computed tomography images and provides anatomic data to enable safe middle hepatic vein-guided liver resection. MethodsFollowing simulation modeling of the hepatic vasculatures, reconstructed MHV data was pooled from 35 healthy liver donors. Yields of the MHV tributaries were analyzed to enable MHV-guided liver resection. ResultsA total of 252 tributaries were identified in the 35 donors. The MHV yielded fewer tributaries from its anterior and posterior aspects than from its right-side and left-side aspects (40 [15.9%], 13 [5.2%], 93 [36.9%], and 106 [42.1%], respectively). The MHV tributaries from the anterior and posterior aspects were smaller in diameter than those from the right-side and left-side aspects (median, 3.0, 2.0, 4.8, and 4.0 mm, respectively). DiscussionOur simulation revealed that MHV dissection from the anterior or posterior aspect poses a lower risk of injury to the MHV tributaries compared to dissection from either lateral aspect. In addition, MHV dissection from the anterior or posterior aspect allows for safer identification and isolation of the thick MHV tributaries originating from the lateral aspects. Ideally, the anterior or posterior aspect of the MHV should be accessed and exposed before the lateral aspects are dissected to minimize the risk of MHV tributary injury.

Pure laparoscopic versus open right hepatectomy in living liver donors: which is longer bench-surgery time

Background: The aim of the study was to measure bench-surgery time in pure laparoscopic donor right hepatectomy (PLDRH) in comparison with those of conventional donor right hepatectomy (CDRH). Methods: We retrospectively reviewed the medical records of 514 donors who underwent living donor liver transplantation be tween January 2012 and December 2019 at Seoul National University Hospital. We divided it into two periods: when almost only CDRH was performed and the second period during which PLDRH was standardized. Results: The mean bench-surgery time (49.3 vs. 39.5 minutes; P=0.00) was longer in the PLDRH group than the CDRH group. We performed the analysis while excluding the factors affecting the bench-surgery time in both groups. First, we analyzed except the patients who had undergone direct venoplasty or Y-graft patch reconstruction of two portal veins. After that, we excluded the pa tients who had reconstruction of more than three openings of middle hepatic vein tributaries and no reconstruction of those (right hemi-liver graft). Lastly, we excluded the patients who underwent venoplasty of inferior hepatic vein(s) in back-table procedures. In all three subgroup analyses, the mean bench-surgery time was also longer in the PLDRH group than the CDRH group (47.4 vs. 38.4 minutes, P=0.00; 48.7 vs. 37.4 minutes, P=0.00; 48.3 vs. 36.6 minutes, P=0.00). Conclusions: The bench-surgery time takes longer in the PLDRH group regardless of reconstruction of type II or III portal vein variations and liver graft outflow or not.

Recipient Hepatic Vein as an Autologous Vascular Graft for Hepatic Vein Reconstruction in Living Donor Liver Transplantation.

The outflow congestion of liver grafts is potentially life-threatening in living donor liver transplantation (LDLT) using the right liver graft (RLG) devoid of the middle hepatic vein (MHV) or the right posterior section graft (RPSG). To prevent congestion of the right anterior section of an implanted RLG, it is crucial to reconstruct donor MHV tributaries using vascular grafts. Congestion of the right hepatic vein (RHV) due to an anastomotic stricture or trunk twisting can also be prevented by effective venoplasty using vascular grafts.

A Feasible Technique for Middle Hepatic Vein Reconstruction in Right Lobe Liver Transplantation: Usage of Autologous Portal Vein With Bench Recanalized Umbilical Vein Graft.

Background Middle hepatic vein (MHV) reconstruction is necessary to achieve a good outcome in right lobe liver transplantation. Many successful reconstruction methods have been reported as there are anatomical variations in MHV tributaries. Some methods are time consuming to perform routinely and other methods are not applicable in all anatomical variations. Large series which describe routine use of portal vein (PV) and bench recanalized umbilical vein (UV) graft have not been reported. In this paper, we report our experience of this novel technique of MHV reconstruction as a standard protocol. Material and method From February 2017 to December 2018, there were 301 patients who received right lobe liver transplant in our Centre, and the new MHV in 268 grafts were reconstructed with autologous PV and bench recanalized UV. The length of the vein graft and distance between segment 5 branch and MHV orifice were measured. We divided these patients into 3 risk groups according to the MHV drainage area (congestion volume) of the right lobe (Low risk: under 30%, Medium risk: 31 to 45%, High risk: over 45%). Clinical data was collected, and perioperative data were compared between the 3 groups. Results The distance from V5 to MHV orifice, PV autologous graft only, and PV&UV was 9.5±2.5, 7.2±1.5, 13.5±2.2 cm respectively. The patency rate of our reconstructed MHV was 97% and 89% at 1 month and 1 year respectively. There was no significant difference in perioperative data among the 3 groups. The survival in medium and high groups were statistically equivalent to that in low risk group. Conclusion Autologous portal with bench recanalized umbilical vein graft shows a high patency rate and achieves satisfactory outcome in grafts with large MHV drainage area. This graft is able to deal with all the MHV tributary variations by a single method.

Venous drainage of the left liver: an evaluation of anatomical variants and their clinical relevance

To evaluate the variations in venous drainage from the left liver. A retrospective evaluation was performed of all consecutive abdominal computed tomography (CT) examinations at a tertiary referral facility between 1 January and 30 June 2018. Osirix (Pixmeo SARL, Bernex, Switzerland) was used to examine the major hepatic veins and their tributaries in each scan. The classification of variants as proposed by Nakamura and Tsuzuki was used to describe the findings. The following information was collected: ramification pattern, number, length and diameter of middle (MHV) and left (LHV) hepatic vein tributaries. Two researchers collected data independently, and the average measurements were used as the final dimensions. Of 102 examinations evaluated, only 27 demonstrated the conventional venous drainage patterns. The LHV and MHV combined to form a common trunk that emptied into the inferior vena cava (IVC) in 75 (73.5%) cases. The common trunk had a mean length of 8.89 mm and mean diameter of 20.18 mm. Other patterns included Nakamura and Tsuzuki type I (27.5%), type II (29.4%) and type III variants (16.7%). In addition, 4.9% of patients had absent superior middle veins and 80% had supernumerary short hepatic veins (4%). Only 26.5% of patients in this population had conventional venous drainage from the left liver. Surgeons and radiologists in hepatobiliary practice should be aware of these variants in order to minimise morbidity when performing invasive procedures.

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.

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). 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. 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. 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.

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

BackgroundCongestion 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). MethodsWe 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. ResultsThe 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. ConclusionThe 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.

Middle hepatic vein reconstruction in adult right lobe living donor liver transplantation improves recipient survival

BackgroundThe efficacy and necessity of middle hepatic vein (MHV) reconstruction in adult-to-adult right lobe living donor liver transplantation (LDLT) remain controversial. The present study aimed to evaluate the survival beneficiary of MHV reconstructions in LDLT. MethodsWe compared the clinical outcomes of liver recipients with MHV reconstruction (n = 101) and without MHV reconstruction (n = 43) who underwent LDLT using right lobe grafts at our institution from January 2006 to May 2017. ResultsThe overall survival (OS) rate of recipients with MHV reconstruction was significantly higher than that of those without MHV reconstruction in liver transplantation (P = 0.022; 5-yr OS: 76.2% vs 58.1%). The survival of two segments (segments 5 and 8) hepatic vein reconstruction was better than that of the only one segment (segment 5 or segment 8) hepatic vein reconstruction (P = 0.034; 5-yr OS: 83.6% vs 67.4%). The survival of using two straight vascular reconstructions was better than that using Y-shaped vascular reconstruction in liver transplantation with two segments hepatic vein reconstruction (P = 0.020; 5-yr OS: 100% vs 75.0%). The multivariate analysis demonstrated that MHV tributary reconstructions were an independent beneficiary prognostic factor for OS (hazard ratio=0.519, 95% CI: 0.282–0.954, P = 0.035). Biliary complications were significantly increased in recipients with MHV reconstruction (28.7% vs 11.6%, P = 0.027). ConclusionsMHV reconstruction ensured excellent outflow drainage and favored recipient outcome. The MHV tributaries (segments 5 and 8) should be reconstructed as much as possible to enlarge the hepatic vein anastomosis and reduce congestion.

Conceptual framework of middle hepatic vein anatomy as a roadmap for safe right hepatectomy

BackgroundWhile the middle hepatic vein (MHV) guides parenchymal transection during right hepatectomy, its most proximal tributaries can be difficult to identify, and injury to its tributaries can be a source of major bleeding. MethodFollowing simulation modeling of right hepatectomy, reconstructed MHV data was pooled from 40 patients. MHV-tributaries and MHV-relationship to the portal pedicle were mapped out to facilitate their identification from the beginning of parenchymal transection. ResultsHotspots for injury were identified: A median of 1 (1–3) tributaries draining segment 5 (V5) were within 45–90mm from the MHV termination, and 16mm above and 22mm caudal to the portal trunk. Simulation demonstrated a constant anatomic relationship between portal pedicle and the proximal MHV. A median of 2 (0–4) tributaries draining segment 8 (V8) were located 9–35mm from the MHV termination. This information was compiled into an “MHV-road-map” demonstrating 86% of the MHV tributaries at risk for significant bleeding are within 15mm of the MHV, while only thin tributaries are located in the outer area. ConclusionsThe MHV-road-map led to a peripheral-to-central parenchymal transection approach to minimize the risk of MHV-injury thereby reducing bleeding during open and minimally invasive right hepatectomy.

The Anterior Sector Venous Outflow Reconstruction using Recipient’s Superficial Femoral Vein in Adult Right Lobe Living Donor Liver Transplantation

Special attention must be paid in hepatic vein reconstruction to avoid outflow block in living donor liver transplantation (LDLT) with a right lobe graft. To reconstruct the middle hepatic vein (MHV) tributaries, the great saphenous vein, external iliac vein, and ovarian vein as well as portal vein or hepatic vein from the removed liver have been usually used as vein graft because of easy availability, however, these vessels had disadvantages regarding there caliber and length. The superficial femoral vein (SFV) has similar caliber as MHV and enough length (about 15cm) of SFV can be harvested from the recipient with no major complication. We decided to use SFV to reconstruct MHV tributaries in end-to-side anastomosis fashion during bench surgery. After anastomosis, SFV graft looked like MHV itself. For graft implantation, the donor right hepatic vein (RHV) was anastomosed to IVC at first, portal reconstruction was followed. After reperfusion, SFV graft was anastomosed to IVC on the left side of RHV anastomosis site. This technique was indicated in two cases of our LDLT. First case was 49-year-old male patient suffering from alcoholic liver cirrhosis. Both V5 and V8 tributaries were considered to be necessary to reconstruct by preoperative 3D simulation of perfusion area. Both V5 and V8 were reconstructed using SFV graft. Second case was 62-year-old male patient suffering from HBV cirrhosis and HCC. V5 tributary was reconstructed using SFV graft. All these tributaries have been patent excellently on 18 and 15 months after LDLT, respectively. MHV tributaries reconstruction using recipient’s SFV might be feasible and effective method in LDLT.

Doppler ultrasound follow-up of middle hepatic vein tributaries-interposition vessel graft in recipients of living donor liver transplantation using modified right lobe grafts.

To investigate the value of Doppler ultrasound (US) in recipients of living donor liver transplantation (LDLT) using modified right-lobe grafts (mRLGs) with obstruction of the middle hepatic vein tributaries (MHVTs)-interposition vessel graft (IVG). This study included 240 consecutive LDLT recipients in whom 564 MHVTs (>5 mm) were reconstructed using IVG. Regular follow-up Doppler US was performed to assess the patency of the MHVTs-IVG and, if there was an obstruction, to evaluate for the establishment of collateral drainage. MHVTs with obstruction were subdivided into those with and without intrahepatic veno-venous collaterals on Doppler US and were correlated with CT scans. MHVTs-IVG obstruction was identified in 137 patients with 227 MHVTs on follow-up Doppler US (6.2 ± 4.7 months). 90 patients with 149 MHVTs in whom the time interval between Doppler US and contrast-enhanced dynamic CT scans was<1 week were classified into either collateral (68 patients with 121 MHVTs) or non-collateral (22 patients with 28 MHVTs) groups. The presence of intrahepatic veno-venous collaterals on Doppler US were significantly related to no remarkable hepatic venous congestion on CT by both per-patient and per-vein analyses (66 of 68 patients (97.1%) and 118 of 121 MHVTs (97.5%), p < 0.001 andp < 0.001, respectively). On Doppler US follow-up of LDLT recipients using mRLGs, identification of intrahepatic veno-venous collaterals associated with obstruction of MHVTs-IVG suggests no remarkable hepatic venous congestion. Advances in knowledge: When an obstruction of a MHVTs-IVG is encountered on Doppler US follow-up of LDLT recipients using mRLGs, no further evaluation with CT is warranted if intrahepatic veno-venous collaterals are observed on Doppler US, as this finding suggests no remarkable hepatic congestion.

Thrombotic Ringed Polytetrafluoroethylene Graft With Infection After Living-Donor Liver Transplantation

BackgroundThe safety of the living donor in living-donor liver transplantation (LDLT) is always the first priority, meanwhile, the graft-to-recipient weight ratio (GRWR) and the anatomy of the liver allograft must also not be compromised in order to warrant tranplatation success. When it comes to the allograft of the right lobe of the liver without the middle hepatic vein (R–M), the outflow and adequate drainage for the territory of middle hepatic vein (MHV) is one critical concern. Despite publications in some high-volume transplant centers on the positive results of using expanded polytetrafluoroethylene (ePTFE) grafts to substitute those of autologous veins, complications related to the ePTFE graft have not been well discussed. MethodsFrom July 2012 to June 2016, 129 adult patients who underwent living donor liver transplantation in Taipei Veterans General Hospital were analyzed. There were 3 cases of adjacent organ erosion with gas bubbles in the lumen of an ePTFE graft, including gastrointestinal (GI) tract penetration in 2 out of the first 15 cases that used the venous graft of ringed expanded polytetrafluoroethylene (rPTFE). The patient survival rate during this period was compared and radiological findings of rPTFE function and clinical signs of erosion with infection were also examined to raise the concerns of safety as well as early detection of complications of rPTFE. ResultsThe overall 1-year patient survival rate was 90%, of which the right lobe wih MHV (R+M) group was 93.5% and the R–M group was 91.9%. For the mean of GRWR, the R+M group was 1.05 ± 0.19 and R–M group was 1.19 ± 0.27, while those who needed reconstruction with vein grafts was 0.96 ± 0.11. Among the R–M group, 24 out of 88 cases (27.3%) needed reconstruction of MHV tributaries. Of the 24 cases, 15 cases were done with rPTFE and the 1-year patient survival rate of the rPTFE group was 73%, which is significantly worse (P = .008) than the non-rPTFE (89%) and non-reconstructed (97%) groups. The mean GRWR is significantly higher (P = .001) in the non-reconstructed group (1.19 ± 0.27) than in the rPTFE (0.99 ± 0.11) and non-rPTFE (0.94 ± 0.11) groups. The venous grafts patency rate between the different graft types is no different, and there is also significance in warm ischemic time (P = .009) between the non-reconstructed (49 ± 15), rPTFE (81 ± 51), and non-rPTFE (56 ± 18) groups in the mean minutes. ConclusionIn cases of fever of unknown cause in patients receiving LDLT with rPTFE graft, a regular computed tomography (CT) scan with contrast and gas bubbles within the graft lumen is the best way for early detection of graft related infection and suspicious GI tract penetration. To decrease the risks of tissue reaction induced by ePTFE graft in LDLT, omentum patches or other inert agents can be introduced as a buffer between the graft and adjacent organs, especially the GI tracts. However, research in material science shall be explored to solve the problem in the future.

Effect of Middle Hepatic Vein Tributaries Preserving Technique Until Just Before Graft Retrieval on Donors' Surgical Outcomes in Living Donor Liver Transplantation

BackgroundThe technique of preserving the major tributaries of the middle hepatic vein (MHV) (V5 and V8) until just before graft retrieval is beneficial to minimize congestion time of the graft. However, it remains unclear whether this technique exerts a burden on donors in terms of operative time, blood loss, and postoperative hepatic dysfunction. In this study we investigated adverse effects of the MHV tributaries preserving technique until immediately before graft retrieval on donors' surgical outcomes. MethodsData from 71 donors who underwent right hepatectomy without MHV for a liver transplantation at our hospital from January 2002 to August 2016 were retrospectively reviewed. Donors were divided into 3 groups as follows: group 1 (n = 12), no MHV tributary reconstruction; group 2 (n = 33), single MHV tributary reconstruction; group 3 (n = 26), 2 or 3 MHV tributaries reconstruction. Donor operation time, blood loss, proportion of the remnant liver, maximum postoperative total bilirubin, aspartate aminotransferase, alanine transaminase, minimum platelets, prothrombin time, albumin level, number of days in hospital from surgery to discharge, and surgical complications were compared. ResultsCompared with groups 2 and 3, group 1 exhibited shorter average operational time and less average blood loss, but the difference was not significant. Comparisons of all other factors indicated no significant differences. ConclusionThe technique of preserving the major tributaries of the MHV until just immediately before graft retrieval does not appear to impose an apparent burden on donors.

Split liver technique with middle hepatic vein reconstruction on livers from transplant hepatectomies: a useful tool for surgical improvement.

Livers removed during transplant hepatectomies could represent a useful anatomic ex vivo resource for surgical training, since they are intact and not altered by post-mortem changes yet. The aim of this study is to investigate the effectiveness of such kind of surgical training applied on some hepatic surgery techniques. In the present paper, we focused on split liver operation and middle hepatic vein (MHV) bipartition/reconstruction, since these procedures have a quite long learning curve. Seven native livers were submitted to split liver procedure by a senior resident assisted by a fully trained hepatic surgeon. Pre-splitting ultrasound mapping was compared to pre-operative CT scan. The whole graft was divided into two hemi-livers and the MHV into two hemi-confluents and reconstructed by venous or arterial patches obtained by deceased donor iliac homograft. Water tightness of the anastomosis was confirmed by hydro-pneumatic test and bench portal perfusion. Reduction in operating time was considered an indirect indicator of surgical skill improvement. In all cases, the US confirmed the anatomical distribution of MHV tributaries observed by pre-transplant CT scan. The "ex situ" splitting procedures and MHV bipartition and reconstruction were performed in all native livers in the usual time required for liver transplantation bench surgery (range 50-75min). Liver grafts removed during hepatectomy could represent a useful resource of intact organs to perform surgical training and boost surgical confidence. In our initial experience, the study of venous drainage of the MHV and application of liver splitting technique and MHV reconstruction resulted technically feasible.

Reconstruction of hepatic venous tributary in right liver living donor liver transplantation: The importance of the inferior right hepatic vein.

Special care must be taken in hepatic vein reconstruction to avoid outflow block in living donor liver transplantation (LDLT) with a right liver graft. We have used cryopreserved homologous veins to reconstruct the right hepatic vein (RHV), middle hepatic vein (MHV), MHV tributaries (V5 and V8), and inferior right hepatic vein (IRHV). The reconstruction of V5, V8, and IRHV was based on the estimated congestive volume, calculated by the computed tomography volumetry, to secure the functional graft volume of 40% of the recipient standard liver volume. Among 262 right liver LDLT recipients, the number of reconstructed RHVs, MHVs, V5s, V8s, and IRHVs was 262, 48, 110, 111, and 147, respectively, and the overall patency was 95%, 100%, 36%, 58%, and 86%, respectively. Although the patency of the RHVs and MHVs was satisfactory, that of the V5s, V8s, and IRHVs was suboptimal. Patency of the IRHVs (86%, 126/147) was significantly better than that of both V5s (36%, 40/110) and V8s (58%, 64/111; P < 0.001). In addition, the estimated volume drained by IRHVs was significantly greater than that of V5s and V8s (IRHV, 176 ± 92 mL; V5, 105 ± 49 mL; V8, 127 ± 60 mL; P < 0.001). The patency of IRHV was significantly improved by applying the double inferior vena cava method (93%, 94/101) when compared to the direct anastomosis to vena cava (68%, 25/37; P < 0.001). The IRHV functioned as a main drainage route in cases of an obstructed RHV. In conclusion, reconstruction of the IRHV is recommended, not only to improve the functional reserve of the graft, but also to secure multiple drainage routes of the graft.

Synthetic graft for reconstruction of middle hepatic vein tributaries in living-donor liver transplant.

In middle hepatic vein dominant livers, the anterior segment of the right lobe of the liver (segments V and VIII) drains mainly into the middle hepatic vein. In these donors, when right lobe grafts are procured without the middle hepatic vein, the graft may harbor large segment V and/or VIII veins that need reconstruction to avoid graft congestion and subsequent graft dysfunction. Draining these middle hepatic vein tributaries using autologous or cryopreserved vessels is a solution, despite the possible difficulties of their preparation. However, these vessels are not always available. Our objective was to evaluate the effectiveness and safety of using a synthetic vascular graft. Between January 2012 and October 2013, eighteen adult recipients underwent living-donor liver transplant using right lobe grafts without the middle hepatic vein at Dar Al Fouad Hospital, 6th of October City, Egypt. All grafts had a large tributary of the middle hepatic vein. Eight-mm ringed expanded polytetrafluoroethylene vascular grafts were used to drain 15 segment V vein tributaries and 3 segment VIII vein tributaries directly to the inferior vena cava. Follow-up was done using duplex ultrasound to evaluate the patency of the vascular graft and the liver congestion and the liver function tests including liver enzymes. Intraoperative Duplex ultrasound confirmed patency and absent segmental congestion in all 18 recipients. The vascular graft patency was 17/18 at 1 week (94.4%) and 15/18 at 1 month (83.3%). No recipients developed graft infection at 1 month. Synthetic vascular expanded polytetrafluoroethylene grafts could be used effectively and safely in middle hepatic vein tributary reconstruction to overcome the unavailability of autologous or cryopreserved vessel grafts or just to avoid the additional burden of recovering autologous grafts thus simplifying the procedure.