Reconstruction of a rare variant of the left hepatic vein in a left lateral segment liver graft from a living donor: Technical notes.

Reconstruction of hepatic veins in living donor liver transplantation (LDLT) is often technically challenging and a good venous outflow is essential for survival of the graft and patient. We describe a quadrangular patch venoplasty technique used for the reconstruction of a rare variant of the left hepatic vein (LHV) in a pediatric LDLT with left lateral segment (LLS) graft. Segment II vein in the graft was draining directly into the inferior vena cava (IVC) and segment III vein was draining into the middle hepatic vein (MHV) after receiving a tributary from segment IV so that there were two widely separated ostia at the cut surface. This is one of the rarest variations of the LHV and is so called type 3 variant; it is usually reconstructed using interposition tubular conduits necessitating two separate anastomoses at the IVC.

INTRODUCTION

The emergence of segmental liver transplantation has brought along with it a rebirth and reconsideration of the classic concepts of vascular anatomy of the liver. Variations in the anatomy of the hepatic veins draining the left lateral segment (LLS) are relatively uncommon but are technically challenging if they occur.[1] The literature regarding the reconstruction of type 3 variant of left hepatic vein (LHV) in LLS grafts in living donor liver transplantation (LDLT) is scarce. Here, we describe a quadrangular patch venoplasty technique used for the reconstruction of a type 3 variant of LHV in a pediatric LDLT.

Case and technique

A 2-year-old child with liver failure was referred to our center for liver transplantation. She was diagnosed to have progressive familial intrahepatic cholestasis-1 (Byler's disease) manifesting as jaundice and failure to thrive. In view of progressively worsening condition of the patient and the scarcity of cadaveric organ in our region, a related living donor LLS liver transplantation was planned. Donor liver imaging showed a rare variant of LHV -the so called type 3 variant. Segment II vein in the graft was draining directly into the inferior vena cava (IVC) instead of joining with segment III vein to form a common LHV trunk. Segment III vein was draining into the middle hepatic vein (MHV) after receiving a tributary from segment IV. Volume estimation showed a graft-recipient weight ratio (GRWR) of 3.4.

LLS was harvested from the donor in the standard way. Ostia of segments II and III veins at the cut surface were situated about 2.3 cm apart [Figures 1a and 2a]. The creation of a common truncal anastomotic stump by direct venoplasty was practically not feasible. A preserved iliac vein allograft from a deceased donor of same blood group was available at that time. We prepared a 1.5 × 1.5 cm sized quadrangular venous patch from the iliac vein allograft. The patch was anchored to segment II and III veins at the bench using 7-0 polypropylene sutures to bridge the gap between two veins producing a neo LHV [Figures 1a and 2b]. A 3.5-cm venotomy was made on the anteromedial aspect of the IVC [Figure 2c] and the reconstructed LHV was anastomosed to the IVC using 5-0 polypropylene continuous sutures [Figures 1b and 2d–e].

Figure 1

(a) Reconstruction of segment II and III veins (solid white arrows) at the back table into a single opening using a quadrangular venous patch (white open arrow) (b) Newly created left hepatic vein (black arrow) being anastomosed to the inferior vena cava (white arrow) during implantation

Figure 2

Illustration (a) Type 3 LHV: Note segment III vein draining into MHV and segment II vein draining into IVC. Resection plane for the left lateral segment graft is marked with dotted line (b) A quadrangular venous patch (open arrow) has been used to unite the ostia of segment II and III veins. Orientation sutures are taken on venous patch corners and graft venous sides (c) A venotomy is made on the anteromedial aspect of IVC and orientation sutures are taken for anastomosis with neo LHV (open arrow) (d) Shows posterior layer of anastomosis (black arrow) (e) Completed wide neo LHV-IVC anastomosis

Doppler ultrasound immediately after reperfusion and on postoperative days 1 and 7 showed good triphasic flow in segment II and segment III veins, and the child had an uneventful recovery. Graft function and Doppler ultrasound at 3 months after transplantation were normal.

DISCUSSION

Historically, the shortage of organs from deceased donors for liver transplantation was most profound for children, who require smaller grafts. Reduced liver transplantation or the split liver technique are performed to overcome this shortage in those areas of the world where deceased donor liver transplantation (DDLT) is widely practiced. But in most of the Asian countries where DDLT is still in its budding stage, splitting is seldom performed and LDLT remains the only viable option for children with end-stage liver diseases.

In segmental liver transplantation vascular outflow, with its high degree of variability, is considered equally or even more importantly than vascular inflow. Securing a wide orifice for venous anastomosis is beneficial for accommodating potential graft remodeling-associated distortion of the hepatic vein anastomosis and is the most important strategy to prevent hepatic venous stenosis (HVS).[23] The obstruction of hepatic vein outflow could potentially result in cut surface bleeding, graft congestion, and graft failure, thereby increasing the morbidity and indeed the mortality. Outflow obstruction can result from anastomotic narrowing, twisting, or inadequate drainage of accessory veins in partial liver transplantation and cause severe graft dysfunction resulting either in retransplantation or mortality, especially in those regions where DDLT is seldom practiced.

Preoperative mapping of the hepatic venous system is indispensable for the success of LDLT. The transection plane in the donor liver is determined by the anatomic distribution of hepatic veins of the left liver and adequate graft volume based on an acceptable GRWR.[45] Three variants of LHV have been described in the literature.[16] In type 1 variant (single opening at the cut surface of LLS graft) segment II and III veins join to form a common LHV trunk (occurs in 75% of the cases) that joins the MHV to drain into the IVC, whereas in type 2 (two closely situated openings at the cut surface of LLS graft), there are separate segment II and III veins, each draining as an individual segment into the MHV (14-20% of the cases). Type III variant is the rarest type among the three anatomical variants of the LHV where the segment II vein drains into the IVC as LHV and the segment III vein drains separately into the MHV so that the orifice of the segment II and III veins are widely separated at the cut surface of the LLS graft, as in our case.

Several modified techniques are being used for the LHV reconstruction in LLS liver transplantation and most of them are reported in DDLT. The triangulation technique described by Emond et al. is of proven value in reimplanting the type 1 variant.[7] For the type 2 variant, venoplasty has been used to create a single anastomosis.[8] The type 3 variant is usually reconstructed using vein grafts or iliac artery grafts as interposition tubular conduits necessitating two separate anastomoses at IVC.[1] Reconstructing the individual openings is tedious, challenging, time-consuming, and associated with prolonged warm ischemia and cross-clamping time. Long conduits are prone to kinking or rotation, often leading to outflow obstruction. Our case demonstrates that the use of quadrangular patch venoplasty technique can overcome the difficulties of multiple outflow reconstructions in the type 3 variant of LHV, especially if the segment II and III openings are not amenable for direct unification venoplasty. The use of a quadrangular patch made single anastomosis possible at IVC. Compared to reconstruction using interposition conduit, this technique not only decreases the chance for kinking and rotation but also prevents HVS by securing a wider and shorter anastomosis between LHV and IVC.

CONCLUSION

To conclude, identification of rare variations of the LHV in living donor LLS liver transplantation and its meticulous reconstruction at the back table are necessary to avoid blood loss and graft congestion. Our approach utilizes back-table reconstruction to reduce warm ischemia time and eliminates the need of an additional anastomosis at IVC.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.