Impact of the Reconstruction Material on the Patency of Middle Hepatic Vein in Living Donor Liver Transplantation Using the Right Liver

Pre-operative assessment of living liver donors' liver anatomy and volumes

Decades of experience supports LDLT as a favorable strategy to reduce waitlist mortality. The multiple regenerative pathways of hepatocytes and other hepatic cells justify the rationale behind it. Nonetheless, living liver donation is still underused and its broader implementation is challenging, mostly due to variability in practices leading to concerns related to donor safety. A non-systematic literature search was conducted for peer-reviewed original articles related to pre-operative evaluation of living liver donor candidates. Eligible studies were synthesized upon consensus for discussion in this up-to-date review. Review of the literature demonstrate that the importance of preoperative assessment of vascular, biliary and liver volume to ensure donor safety and adequate surgical planning for graft procurement is widely recognized. Moreover, data indicates that anatomic variants in vascular and biliary systems in healthy donors are common, present in up to 50% of the population. Therefore, comprehensive mapping and visualizations of each component is needed. Different imaging modalities are reported across practices and are discussed in detail. Lastly, assessment of liver volume must take into account several technical and donor factors that increase the chances of errors in volume estimation, which occurs in up to 10% of the cases. Experience suggests that maximizing donor safety and lessening their risks is a result of integrated experience between hepatobiliary and transplant surgery, along with multidisciplinary efforts in performing a comprehensive pre-operative donor assessment. Although technical advances have increased the accuracy of volume estimation, over- or under-estimation remains a challenge that needs further attention.

[Transplantation technologies in pediatric liver resections]

Liver resections with transplantation technologies have been recognized as safe procedures for the last decades. These procedures may be the only curative option or alternative to liver transplantation in some cases. Moreover, these surgeries can also provide parenchyma-sparing liver resection. Nevertheless, higher postoperative morbidity and mortality compared to traditional hepatectomy require careful research of indications for liver resections with transplantation technologies, the role of vascular liver exclusion, methods of vascular reconstructions with or without anticoagulation. These challenges are more important for pediatric surgery due to few literature data on this issue. This review is devoted to liver resections with transplantation technologies.

Technical Refinement to Prevent Hepatic Outflow Disturbance in Right Lobe Living Donor Liver Transplantation: The New Simplified One-Orifice Venoplasty Technique

Middle hepatic vein (MHV) reconstruction is often essential to avoid hepatic congestion and serious graft dysfunction in living donor liver transplantation (LDLT). This article introduces the evolution of our MHV reconstruction technique and the excellent outcomes of a new simplified one-orifice venoplasty. We compared clinical outcomes among 3 types of one-orifice techniques through a retrospective review of 378 recipients who underwent LDLT using a modified right lobe graft at our institution from January 2008 to December 2018; group I (n = 34) received separate outflow reconstruction, group II (n = 166) received the one-orifice technique to create a wider single outflow with patchwork, and group III (n = 178) received the more simplified one-orifice technique in which neo-MHV was reconstructed into the right hepatic vein without patch venoplasty. Patient demographic characteristics did not differ significantly among the 3 groups, but cold ischemic time and operative time in groups II and III were significantly shorter than those in group I. Moreover, the early patency rates of MHV in groups II and III were higher than those in group I. In particular, group I received an MHV or right hepatic vein stenting more frequently than group II or III during the early posttransplant period. In conclusion, this new simplified one-orifice technique could be an effective method to overcome technical difficulties and the outflow disturbance during right lobe LDLT without complex benchwork to create a large outflow.

Middle hepatic vein reconstruction in adult living donor liver transplantation: a randomized clinical trial

BACKGROUND

In adult right lobe living donor liver transplantation (LDLT), venous drainage of the anterior sector is usually reconstructed on the bench to form a neo-middle hepatic vein (MHV). Reconstruction of the MHV for drainage of the anterior sector is crucial for optimal graft function. The conduits used for reconstruction include cryopreserved allografts, synthetic grafts, or the recipient portal vein. However, the ideal choice remains a matter of debate. This study compares the efficacy of the native recipient portal vein (RPV) with PTFE grafts for reconstruction of the neo-MHV.

METHODS

Patients in this equivalence-controlled, parallel-group trial were randomized to either RPV (62 patients) or PTFE (60 patients) for use in the reconstruction of the neo-MHV. Primary endpoint was neo-MHV patency at 14 days and 90 days. Secondary outcomes included 90-day mortality and post-transplant parameters as scored by predefined scoring systems.

RESULTS

There was no statistically significant difference in the incidence of neo-MHV thrombosis at 14 days (RPV 6.5 per cent versus PTFE 10 per cent; P = 0.701) and 90 days (RPV 14.5 per cent versus PTFE 18.3 per cent; P = 0.745) between the two groups. Irrespective of the type of graft used for reconstruction, 90-day all-cause and sepsis-specific mortality was significantly higher among patients who developed neo-MHV thrombosis. Neo-MHV thrombosis and sepsis were identified as risk factors for mortality on Cox proportional hazards analysis. No harms or unintended side effects were observed in either group.

CONCLUSION

In adult LDLT using modified right lobe graft, use of either PTFE or RPV for neo-MHV reconstruction resulted in similar early patency rates. Irrespective of the type of conduit used for reconstruction, neo-MHV thrombosis is a significant risk factor for mortality.

REGISTRATION NUMBER

CTRI/2018/11/016315 (www.ctri.nic.in).

Venous Reconstruction During Pancreatectomy Using Polytetrafluoroethylene Grafts: A Single-Center Experience with Standardized Perioperative Management

BACKGROUND

Although primary end-to-end anastomosis is preferred for portal vein-superior mesenteric vein (PV-SMV) reconstruction, interposition graft use may be required in some situations. We investigated the efficacy of polytetrafluoroethylene (PTFE) grafts when used during pancreatectomy in this context.

METHODS

From 2014 to 2019, 19 patients who underwent pancreatectomy requiring PV-SMV reconstruction using ringed PTFE grafts were entered prospectively into a clinical database (NCT02871336, CNIL No. Sy50955016U). Unfractionated heparin was used during the first 24 h postoperatively. The administration of low-molecular-weight heparin was initiated twice a day (two injections of 1 mg/kg enoxaparin) on postoperative day 2 and was continued until the first clinical follow-up. Patency was assessed by CT scan before home discharge. Patients were switched to antiplatelet therapy (75 mg of aspirin-based drug Kardegic^®) without a deadline.

RESULTS

Pancreatoduodenectomy was the most commonly performed procedure (15 patients, 79%), and pancreatic duct adenocarcinoma was the predominant etiology (17 patients, 89%). The median PTFE graft diameter and length were 10 mm and 8 cm, respectively. The median clamping time was 25 min. The overall severe morbidity and 90-day mortality values were 21% and 10%, respectively. None of the patients experienced anticoagulation-related morbidity or PTFE graft-related infection. The 6-month PTFE graft patency rate was 68%. Patients who underwent distal pancreatectomy showed a higher late thrombosis rate than those who underwent a pancreaticoduodenectomy (50% vs. 8%, p = 0.049). The median long-term PTFE graft patency duration was 37 months.

CONCLUSIONS

PTFE reconstruction can be safely performed with simple perioperative management in cases requiring interposition graft use.

Hepatic vein in living donor liver transplantation

Right lobe living donor liver transplantation (LDLT) is a major development in adult LDLT that has significantly increased the donor pool by providing larger graft size and by decreasing risk of small-for-size graft syndrome. However, right lobe anatomy is complex, not only from the inflow but also from the outflow perspective. Outflow reconstruction is one of the key requirements of a successful LDLT and venous drainage of the liver graft is just as important as hepatic inflow for the integrity of graft function. Outflow complications may cause acute graft failure which is not always easy to diagnose. The right lobe graft consists of two sections and three hepatic venous routes for drainage that require reconstruction. In order to obtain a congestion free graft, several types of vascular conduits and postoperative interventions are needed to assure an adequate venous allograft drainage. This review described the anatomy, functional basis and the evolution of outflow reconstruction in right lobe LDLT.