The incidence of hepatic venous stenosis is higher in partial liver transplantation. New methods for hepatic venous reconstruction in left liver transplantation, which secure wide anastomosis, were devised and are reported here. In the graft, the right side of the middle hepatic vein or the left side of the left hepatic vein was cut longitudinally and a rectangular-shaped vein patch was attached for venoplasty. In the recipient, after the left and middle hepatic veins were joined, the right side of the middle hepatic vein was cut toward the closed right hepatic vein, making a horizontal cavotomy for anastomosis. Of 92 patients who underwent conventional hepatic vein reconstruction, 3 were complicated by hepatic venous stenosis (median follow-up 43 months). By contrast, there were no hepatic vein complications in the 20 patients who underwent the new technique (7 months). The current method appears to be technically feasible for outflow reconstruction in left liver graft transplantation. (Liver Transpl 2005;11:356–360.)
The limited supply of cadaveric donor organs for liver transplantation has fostered the use of segmental liver grafts with reduced-sized grafts, split liver transplantation, and living donor liver transplantation (LDLT). The use of partial liver grafts, however, demands more meticulous surgical procedures, which results in an increase in vascular complications. The incidence of hepatic venous stenosis (HVS) in partial liver transplantation is higher (2–13%)1, 2 than in whole liver transplantation (1–2%).2, 3
Venography is performed when HVS is suspected based on ultrasonographic findings,4 including a decrease in hepatic venous flow speed, a flat venous flow wave form, dilatation of the peripheral venous tributaries, and decreasing portal flow. Patients are diagnosed with HVS when the pull-through pressure gradient across the anastomotic site is more than 5 mm Hg, at which point balloon angioplasty is performed. Stenosis refractory to angioplasty may be an indication for stent replacement2; however, in partial liver transplantation, stenting is not always secure. Stent dislocation can occur during graft regeneration and pediatric patient growth. Interventional or surgical therapy for HVS is often difficult. When radiologic intervention for HVS fails, reoperation for venous anastomosis5 or retransplantation should be considered.
Early-onset HVS usually originates from technical problems. Securing a wide orifice for venous anastomosis is the most important strategy to prevent HVS. We recently devised a new technique using a venous patch to guarantee a wider outflow tract in a left liver graft.
LDLT, living donor liver transplantation; HVS, hepatic vein stenosis; LHV, left hepatic vein; MHV, middle hepatic vein; RHV, right hepatic vein; SFV, superficial left hepatic vein; IVC, inferior vena cava.
Patients and Methods
From January 1996 to July 2004, 287 patients (216 adults and 71 children) underwent 290 LDLTs at our hospital. The indications for LDLT in these patients were biliary atresia (n = 75), hepatitis C virus cirrhosis (n = 52), primary biliary cirrhosis (n = 52), hepatitis B cirrhosis (n = 29), fulminant hepatitis (n = 28), metabolic disorder (n = 14), cryptogenic cirrhosis (n = 9), primary sclerosing cholangitis (n = 9), autoimmune hepatitis (n = 8), alcoholic liver cirrhosis (n = 4), and others (n = 7). The most commonly used type of graft was the left liver with or without the caudate lobe (n = 112), followed by right liver (n = 107), segments II and III (n = 52), and right lateral sector (segments VI and VII, n = 19).
In August 2003, we made a policy change regarding the surgical technique for left liver graft venous reconstruction. Ninety-two patients received a left liver using the conventional method, and 20 received a left liver using the new technique.
Donor hepatectomy was performed as previously described.6 The harvested liver graft (Fig. 1) was flushed with University of Wisconsin solution, and venoplasty of the graft hepatic veins was performed at the bench. In the original method, left (LHV) and middle hepatic veins (MHV) were venoplastied to make 1 orifice for easier anastomosis.7, 8 When the MHV trunk could not be harvested, the branch of the MHV (V4) was venoplastied.9 In the new method, the right side of the MHV cuff was cut longitudinally, and a rectangular-shaped vein patch was attached to the cuff for venoplasty. When a sufficient venous diameter was not obtained using this method, the left sidewall of the superficial LHV or LHV was cut and patched in the same way (Fig. 2A–E). A circular cuff vein patch was further added when the vein cuff of the liver graft was not sufficient for anastomosis (Fig. 2F).
As for the recipient side, the LHV and MHV were originally connected.7, 10 When the orifice of the combined veins was smaller than that of the graft, venoplasty in the recipient was performed using 3 hepatic veins.11 In the new method, if the length of the right hepatic vein (RHV) cuff was sufficiently preserved for reconstruction, 3 hepatic veins was venoplastied. When the RHV cuff was not long enough, the RHV was closed with a running suture at its root, and a venous patch was used as follows. After the LHV and MHV were joined (Fig. 3A–B), the inferior vena cava (IVC) was cross-clamped above and below the hepatic veins. The right side of the MHV was then cut toward the closed RHV, making a horizontal cavotomy (Fig. 3B). The patch graft was then sutured to the cavatomy site (Fig. 3C–D).
The short hepatic vein was anastomosed to an existing IVC end to side.10 When the orifice of the short hepatic vein was located near those of the LHV and MHV, they were connected with the LHV and MHV using a vein patch. Finally, the hepatic veins of the liver graft were anastomosed with the recipient hepatic veins.
Cryopreserved veins were used when the venous patch grafts from the recipient were not sufficient for venoplasty. They were provided by the University of Tokyo Tissue Bank. The vein grafts were obtained from cadavers or non–heart-beating donors within 24 hours after cardiac arrest. The specimens were packed in a sterile bag and frozen slowly in a programmable freezer. They were stored in liquid nitrogen until use.12
The clinical factors were compared between the 20 patients who underwent left liver transplantation with the new method and the 92 patients who underwent left liver transplantation with the conventional technique. Compared factors included warm and cold ischemic time, graft weight, operation time, blood loss volume, patient age, hospitalization duration, follow-up period, and survival. Survival and HVS-free rates were analyzed by log-rank test, and other parameters were analyzed using Student's t-tests. A P value of less than .05 was considered statistically significant. Data are shown with median and range.
Mortality and Morbidity
In the 92 patients who underwent the conventional method, 3 patients experienced HVS (3%). They were successfully treated with patch venoplasty (62 months after LDLT), venoatrial anastomosis (5 months after LDLT), and balloon angioplasty (4 months after LDLT). By contrast, all 20 patients who underwent the new technique survived LDLT without HVS with a median follow-up of 7 months. Postoperative complications of these 20 patients included thrombogenic microangiopathies (n = 2), acute rejections (n = 2), bile duct stenosis (n = 1), portal vein thrombosis (n = 1), pulmonary embolism (n = 1), peritonitis of methicillin-resistant Staphylococcus aureus (n = 1), and bowel obstruction (n = 1). Patient survival and HVS-free curves are shown in Fig. 4A and B . There was no significant difference in either comparison.
Vein grafts were used to patch the grafts on the MHV side only (n = 6) or on both sides (n = 7). A circular cuff vein patch was used for 5 patients. The MHV trunk was preserved, and the V4 received plasty in 2 grafts; short hepatic veins were connected with the LHV and MHV orifices at the bench in 2 grafts.
Venous grafts used in the graft included left portal veins of the recipients (used in 8 sites), peripheral parts of right portal veins of the recipients (n = 6), cryopreserved venous grafts (n = 6), and recipient RHV (n = 4) and LHV (n = 1). Three kinds of veins were used in 1 graft, and 2 kinds of veins were used in 3 grafts. Cryopreserved vein grafts were from portal veins (n = 2), femoral veins (n = 2), superior vena cava (n = 1), and iliac vein graft (n = 1). On the recipient side, a venous patch was used at the incised cava site (n = 14). The vein grafts included RHV (n = 7), left portal veins (n = 7), right portal veins (n = 4), cryopreserved grafts (n = 2, femoral vein and superior vena cava), and an LHV. One patient received 3 kinds of vein grafts, and 5 patients received 2 kinds of vein grafts. Overall, cryopreserved veins were used in 7 patients.
Comparative data are shown in Table 1. Using the new method, the cold ischemic time was significantly longer than when using the conventional method (P < .001).
Table 1. Comparative Data in Patients Who Received Left Liver Transplantation by Conventional or New Methods*
In the initial LDLT experience, end-to-side anastomosis was performed for hepatic vein reconstruction.13 A longitudinal incision was made along the anterior wall of the IVC. Broelsch et al. created a triangular window at the anterior aspect of the IVC.14 Graft hepatic venous branches were joined at the bench7 and were anastomosed end to side to the caval window. Takayama et al. reported that a direct anastomosis of the hepatic veins to a thin IVC can sometimes cause a bend in the IVC at the anastomotic site, which results in outflow occlusion.15 End-to-end vein anastomosis is now generally performed for left liver transplantation. Egawa et al.16 and Soejima et al.17 performed end-to-end anastomosis using the common orifice of the LHV and MHV.
We experienced a 3% incidence of HVS (median follow-up 43 months) using the conventional method. The implanted graft is always smaller than the recipient standard volume in adults and will regenerate in the postoperative course.18 The graft will grow mainly toward the left. The enlarged graft may deform the shape of the anastomosis and obstruct the outflow. The obstruction causes congestion of the graft, leading to a malignant cycle of further graft expansion and dysfunction. Using our new technique, the anastomosis is lengthened by adding a venous patch. Long preservation of recipient hepatic veins allows for the formation of a reservoir between the liver graft and recipient IVC.
A cryopreserved vein was used for patch venoplasty when an autograft was not available or was not sufficient for reconstruction. The primary concern in venous reconstruction using cryopreserved vein grafts is graft obstruction or the possibility of narrowing over the long term. Kuang et al.19 used cryopreserved grafts for the portal vein interposition (iliac vein or saphenous vein, n = 7) and the hepatic artery interposition (saphenous vein, n = 2) in LDLT. Vein graft complications were observed in 8 of 9 grafts, including aneurysm (n = 4), thrombosis (n = 3), and stricture (n = 1). Their discouraging short-term results indicated that the use of cryopreserved veins should be minimized. Cryopreserved veins might not always be necessary in most grafts except for those with V4 to be reconstructed.
In left liver transplantation, a vein graft was used to enlarge the hepatic vein anastomois. Our new method might be useful for the prevention of HVS, although the method requires meticulous surgical techniques. The indication of the current technique in left liver grafts remained unclear, and long-term follow-up is necessary to confirm the feasibility of this new method.