Raising-flap technique for outflow reconstruction in living donor liver transplantation

Living donor liver transplantation has been adopted as one of the solutions for overcoming the graft shortage for adult patients with end-stage liver disease waiting for liver transplantation.1 Balanced portal vein and hepatic artery inflows and adequate venous outflow are crucial factors for successful outcomes after living donor liver transplantation.2 In the absence of satisfactory graft venous drainage, the portal inflow has damaging effects on the graft: it delays the graft's regenerative capacity and thus leads to the type of hepatic dysfunction known as small-for-size syndrome. After the inclusion of the middle hepatic vein (MHV), the outflow tract invariably becomes larger, and this causes a caudal shift of the orifice. In such situations, the conventional anastomosis technique is not feasible, and especially in the presence of a small-caliber inferior vena cava (IVC), the horizontal slit in the IVC for the triangular opening does not provide adequate venous drainage; this increases the pull effect on the IVC and stretches the graft veins. Also, any further delay in the anastomosis will only increase the warm ischemia time. Here we describe a raising-flap technique for outflow reconstruction: this technique not only provides a larger outflow orifice for venous drainage but also avoids undue medial pull on the graft hepatic vein. This technique allows more caudal extension of the IVC opening and covering of the triangular hepatic venous orifice of the graft with a flap without stretching of the hepatic veins. After the graft is harvested and the native liver is explanted, initial efforts are made to achieve hemostasis around the retrohepatic area. When the graft liver is ready, the IVC is cross-clamped both above and below. With the help of Potts scissors, cavotomy is performed at the base of the right hepatic vein (RHV) along its insertion at the IVC, and this is continued caudally parallel to the IVC border for approximately 3 to 4 cm or even longer as required (from point A to point B; see Fig. 1A). A flap is raised by the continuation of the cavotomy from the lower point toward the sutured end of the left hepatic vein onto the IVC; this forms an isosceles triangle (from point B to point C; see Figs. 1B and 2B). The lateral extension of the cavotomy can be lowered if that is necessary. The upper and lower ends of the graft hepatic veins are initially secured to similar ends of the right side of the triangle with the help of stay sutures (with reference to points A and D; see Figs. 1B and 2C). The posterior wall of the hepatic vein of the graft is sutured to the right edge of the triangle with continuous running 5-0 Prolene sutures (from point A to point D; see Fig. 1C). After the completion of the posterior layer, the right edge of the flap is then sutured to the anterior-superior margin of the graft outflow tract (from point A to point B of the triangle; see Figs. 1D and 2D). The lower half of the left leaf of the flap is then sutured to the anterior-inferior margin of the graft hepatic vein; usually, the same suture material is continued from the right edge (from point B to the midpoint of the left edge of the flap). At point D, both suture ends are tied together, and the anterior end is continued for the rest of the anastomosis. The small opening remaining at the base of the IVC is now sutured, and the anastomosis is completed (Fig. 1E,F). This last step can also be modified with a triangular patch graft (either a polytetrafluoroethylene graft or a venous graft) to cover the small defect at the base of the flap, and this makes it completely tension-free. In experienced hands, the average time for this anastomosis is approximately 10 minutes. The raising-flap technique has the crucial advantage of avoiding a pull effect on the graft vein, and thus the probability of outflow stenosis due to stretching is almost eliminated. The reconstruction of the vascular outflow tract of partial liver grafts has received considerable attention in the past, especially in the setting of right liver grafts with undrained segments.3 Traditionally, the hepatic vein anastomosis in right lobe living donor liver transplantation is performed by the joining of the graft RHV to the recipient RHV.4 With other conventional techniques described elsewhere, longitudinal and transverse cuts are made in the IVC to form a large triangular opening matching the donor venoplasty.5 This technique has also been modified by caudal shifting of the hepatic vein anastomosis to make better anastomoses feasible in certain situations.5 Some centers also use longitudinal cavotomy to allow a large hepatic vein anastomosis, but with a larger hepatic vein diameter, this does not provide a satisfactory outflow channel. A small-caliber IVC is a challenging additional factor itself above all else. Takemura et al.6 experienced a 3% incidence of hepatic vein stenosis (median follow-up = 43 months) with the conventional method. The raising-flap technique is suitable for a larger hepatic vein orifice, especially after back-table venoplasty of graft veins. The wide cavotomy, which is covered by the flap, provides satisfactory venous drainage and reduces the stretching of hepatic veins and subsequent hepatic vein stenosis. The severity of the tissue congestion caused by interrupted venous drainage and inadequate outflow is highly variable among grafts. Severe congestion in the anterior segment has been reported to occur in right lobe grafts without the MHV, and this leads to massive ascites and graft dysfunction.4, 7, 8 To prevent congestion in the anterior segments, some institutions have preferred the inclusion of the MHV in the graft. Liu et al.9 even chose an extended right lobe graft with the MHV. At our institution, we use a modified technique that includes the MHV in the graft and preserved segment 4b venous drainage in the donor liver with subsequent venoplasty of the MHV and the RHV; this makes the outflow tract unduly large in some cases. In conclusion, the outflow venovenous anastomosis is a crucial aspect of orthotopic liver transplantation with IVC preservation. A wide ostium is indispensable for the prevention of venous obstructions. Our modified technique ensures a wide venous anastomosis and thus prevents any hepatic outflow disturbances. Long-Bin Jeng, M.D.1,2 Ashok Thorat, M.D.2 Ping-Chun Li, M.D.1,2 Ming-Li Li, M.D.2,4 Horng-Ren Yang, M.D.1,2 Chun-Chieh Yeh, M.D.1,2 Te-Hung Chen, M.D.2,4 Chia-Hao Hsu, M.D.2,4 Shih-Chao Hsu, M.D.2,4 Kin-Shing Poon, M.D.3,4 1School of Medicine College of Medicine China Medical University Taichung, Taiwan 2Department of Surgery and Organ Transplantation Center and 3Department of Anesthesiology China Medical University Hospital Taichung, Taiwan 4China Medical University Taichung, Taiwan