Review Article  

Management of the middle hepatic vein and its tributaries in right lobe living donor liver transplantation Peng-Fei Yu, Jian Wu and Shu-Sen Zheng Hangzhou, China

BACKGROUND: Left liver graft from a small donor will not meet the metabolic demands of a larger adult recipient. To overcome the problem of graft size insufficiency, living donor liver transplantation (LDLT) using the right lobe has become a standard method for adult patients. As the drainage of the median sector (segments Ⅴ, Ⅷ and Ⅳ) is mainly by the middle hepatic vein (MHV), the issue of whether the MHV should or should not be taken with the graft or whether the MHV tributaries (Ⅴ5, Ⅴ8) should be reconstructed in the recipient remains to be settled. DATA SOURCES:  An English-language literature search was conducted using MEDLINE (1985-2006) on right lobe living donor liver transplantation, middle hepatic vein, vein graft, hepatic venoplasty and other related subjects. RESULTS: Some institutions had proposed their policy for the management of the MHV and its tributaries. Dominancy of the hepatic vein, graft-to-recipient weight ratio, and remnant liver volume as well as the donor-torecipient body weight ratio, the volume of the donor's right lobe to the recipient's standard liver volume and the size of MHV tributaries are the major elements for the criteria of inclusion of the MHV, while for the policy of MHV tributaries reconstruction, the proportion of congestive area and the diameter of the tributaries are the critical elements. Optimal vein grafts such as recipient's portal vein and hepatic venoplasty technique have been used to obviate hepatic congestion and venous drainage disturbance.

Author Affiliations: Department of Hepatobiliary Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China (Yu PF, Wu J and Zheng SS) Corresponding Author:  Shu-Sen Zheng, MD, PhD, FACS, Department of Hepatobiliary Surgery, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China (Tel: 86-571-87236601; Email: [email protected]) © 2007, Hepatobiliary Pancreat Dis Int. All rights reserved.

CONCLUSIONS:  Taking right liver grafts with the MHV trunk (extended right lobe grafts) or performing the MHV tributaries reconstruction in modified right lobe grafts, according to the criteria proposed by the institutions with rich experience, can solve the congestion problem of the right paramedian sector and help to improve the outcomes of the patients. The additional use of optimal vein grafts and hepatic venoplasty also can guarantee excellent venous drainage. (Hepatobiliary Pancreat Dis Int 2007; 6: 358-363) KEY WORDS: right lobe living donor liver transplantation;  middle hepatic vein;  vein graft;  hepatic venoplasty

Introduction

L

iving donor liver transplantation (LDLT) is considered as the main therapeutic option for the end stage liver disease.[1] Since the first adult-to-child LDLT succeeded in 1989, LDLT has undergone an extension from pediatric liver transplantation using left lateral segment grafts to adult liver transplantation using mainly right lobe grafts.­[2] As cadaveric organ shortage becomes a critical problem, LDLT is now widely performed to expand the donor pool.[3] LDLT using the right lobe graft is now a standard procedure for adult patients[4] in order to alleviate the problem of graft size insufficiency. It is known that hepatic venous outflow of the median sector (corresponding to Couinaud segments Ⅴ, Ⅷ and Ⅳ) is drained mainly into the middle hepatic vein (MHV).[5] As a result, preservation of MHV outflow drainage plays an important role in LDLT with the right lobe. However, inclusion of the MHV in the right lobe graft and the necessity of MHV tributaries reconstruction are still controversial.

358 • Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com

Management of the MHV and its tributaries in right lobe LDLT

Right lobe liver grafts: controversy of inclusion of the MHV Yamaoka et al[6] initially described the utilization of a right lobe graft which was indicated not for size mismatching but for variant hepatic arteries in the left lobe of the donor.[7] Seaman reported the feasibility of use of the right lobe as a living donor graft.[8] With the development of this technique, researchers have extended grafts from the left to the right in order to obviate the problem of graft size insufficiency. Two harvesting methods for right lobe grafts have been proposed: an extended right lobe graft, in which the MHV trunk is included in the grafts, and a modified right lobe graft, in which only the MHV tributaries are included.[9] Right liver grafts with the MHV trunk (extended right lobe grafts) were first performed by the Hong Kong group in 1996, as left lobe grafts from relatively small volunteer donors will not meet the metabolic demand of larger recipients.[3] Seven LDLTs, using this technique, were initially performed under highurgency situations. Although a high postoperative complication rate was reported (donors 29%, recipients 86%), the results are comparable to the best possible outcome in cadaveric transplantation for patients with similar status.[3, 10] Lo et al[11] indicated that the extended right lobe grafts with greater functional liver volume had overcome the restriction imposed by the donor-to-recipient size match and had obvious advantages over the left lobe liver graft which was adopted in the early stage of LDLT.[12] Further studies had been reported by this group, and its researchers recommended absolute inclusion of the MHV in every case,[13, 14] as they demonstrated such inclusion is essential for optimum graft function and patient survival.[13] Meanwhile, another kind of right lobe liver grafts without the MHV (modified right lobe graft) emerged[6, 15, 16] because the surgeons feared of donor risk and important ethical issues, although inclusion of the MHV in a right lobe graft was safe for recipients.[13] The extended right lobe grafts were too extensive as an operation for the donor,[14] and sufficient size of the remnant liver[17]as well as drainage of the segment Ⅳ in the donor could not be guaranteed.[18] However, leaving the MHV with the remnant liver will place the anterior segment (corresponding to segments Ⅴ and Ⅷ) at risk for congestion,[14] and this drainage problem can lead to severe graft dysfunction and septic complications.[19] In such cases, the reconstruction of MHV tributaries have been recommended.[20] Inversely, the use of an

extended right lobe grafts is the best solution for the problem of potential congestion in the anterior segment.[3] Therefore, whether the MHV should or should not be taken with the graft remains the topic of debate on right lobe LDLT. Some centers have introduced their experience in determining the extent of donor hepatectomy either with or without the MHV. de Villa et al[21] described the Kaohsiung principle based on the donor-to-recipient body weight ratio, the volume of the donor's right lobe to the recipient's standard liver volume and the size of MHV tributaries from the anterior segment. This principle was applied in 25 living donor liver transplant operations and procured successful outcomes in both donors and recipients. Later, the Kyoto group, using the three-dimensional reconstructed images of the hepatic vascular anatomy, divided the right lobe graft morphologically into two types: one is a right hepatic vein dominant graft in which the territory draining into the MHV is less than 40% of the right lobe graft, and the other is a MHV dominant graft.[1] Their indication for a right lobe graft with or without the MHV is based on dominancy of the hepatic vein, graft-to-recipient weight ratio, and remnant liver volume.[22] The group performed 217 right lobe LDLTs successfully according to this algorithm. In conclusion, a right lobe graft can be taken with or without the MHV with equally successful outcomes[14] based on the surgeon's experience. However, a right liver graft without the MHV trunk will be more advantageous than an extended right lobe graft according to the donor safety.

Modified right lobe graft: controversy of MHV reconstruction The first LDLT using a right lobe without the MHV (modified right lobe graft) was reported in 1994. It was performed on a 9-year-old girl in Kyoto.[6] Further research was carried out by Marcos et al in the United States.[16] They performed 25 right lobe living donor liver transplants without the MHV, with an excellent patient survival rate of 88%. Early trials revealed that modified right lobe graft did not reconstruct MHV tributaries. As no severe congestion in the anterior segment was observed or even various degrees of congestion developed, patients recovered uneventfully without any sequela. Several researches supported their performance. It is suggested that intrahepatic collateral can develop via the sinusoids,

Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com • 359

Hepatobiliary & Pancreatic Diseases International

short hepatic veins, and occasionally via the portal veins after ligation of the major hepatic veins. This kind of venous collateral can produce venous flow into the right hepatic vein after the ligation of contributaries of the MHV and develop within 10 days of transplantation.[22] Furthermore, even partial congestion in the anterior segment after ligation can be tolerated by the liver.[17] Therefore, these studies indicated the reconstruction of the MHV seemed to be unnecessary. However, Lee et al[23] reported that several patients without MHV reconstruction suffered severe congestion of the right paramedian sector, resulting in progressive graft dysfunction and septic complication. Fan et al[13] proposed that the graft might have sustained injury before the collateral appears to function and it is still controversial whether such collaterals exist in all normal persons. Other researches showed that the relatively poor regeneration of the anterior segment is associated with preoperatively dominant MHV tributaries, indicating that congestion can lead to inadequate regeneration of the affected area.[24] Therefore, the controversy of whether the segment Ⅴ and Ⅷ tributaries should be reconstructed in the recipient is far from settled. In view of these heated debates, some groups have indicated their policy for MHV reconstruction. Sano et al[25] reported that venous congestion in the right liver graft can be assessed by temporary arterial clamping and intraoperative Doppler ultrasonography. They suggested the reconstruction of the hepatic vein or its tributaries if the graft volume excluding the discolored area under arterial clamping was estimated to be insufficient for postoperative metabolic demand (the remaining liver volume was less than 40% of the standard liver volume). MHV reconstruction was performed in 18 of 30 grafts by this group according to their own criteria and all of the grafts showed uneventful functional recovery. Kubota et al[26] proposed if the congestive area of the liver surface appeared after clamping of MHV tributaries and the hepatic artery is larger than half of the surface of the anterior segment, the vein should be reconstructed. Other institutions concerned mainly about vessel diameter. Gyu Lee et al[27] indicated that when the Ⅴ 5 or Ⅴ8 during donor hepatectomy are larger than 5 mm in diameter, the reconstruction of MHV drainage from the anterior segment is recommended, and Mizuno et al[28] suggested 7 mm as the demarcation for reconstruction of MHV tributaries. These groups performed the reconstruction of MHV tributaries, based on their experience, and most of the grafts functioned well postoperatively.

In conclusion, the reconstruction of segment Ⅴ and Ⅷ tributaries was necessary in selective cases according to the policy indicated above. This technique can obviate the potential congestion in the anterior segment and provide a functioning liver mass comparable to an extended right liver graft.[29]

Further considerations and prospects Vein grafts As the reconstruction of MHV tributaries is recommended in selective cases, the optimal vessels for interposition has become a new problem. Gyu Lee et al[27] reported a good result of reconstruction of MHV tributaries of the anterior segment using the great saphenous vein. Cattral et al[30] also described their successful use of the recipient's left portal vein as an interposition graft. Up to now, many types of vein grafts have been used for the reconstruction of the MHV, including the saphenous vein,[31] umbilical vein, left portal vein, mainly from the recipient, and the inferior mesenteric vein and iliac vein,[4, 20, 30] mainly from the donor. Some of the vein grafts, such as the inferior mesenteric vein, umbilical vein, and saphenous vein are too small to maintain flow for a long time and usually need venoplasty to increase its diameter. Other vessels, such as the iliac vein, which has a similar size to the MHV, requires extensive dissection. Recently, some cryopreserved veins have been introduced for hepatic vein reconstruction.[32,  33] This type of vein grafts might be the best way to keep outflow and make the reconstruction technically simple, but such vein grafts may have the problem of obstruction in the long-term observation period.[33] In our institution, we mainly use the recipient's portal vein (main portal vein and its branch) as the interpositional MHV graft. This kind of vein grafts has several advantages over other vessels. Firstly, it is always available and easy to expose after the resection of the liver and eliminates the extensive dissection in the recipient or donor. Secondly, the suitable caliber, thick wall, and natural curvature of the portal vein can reduce the risk of thrombosis[30] after transplantation. Use of optimal vein grafts can obviate hepatic congestion and venous drainage disturbance, but the problem of long-term patency and the operative complexity remain to be solved. Hepatic venoplasty As outflow obstruction may lead to graft dysfunction or loss, hepatic venous reconstruction is

360 • Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com

Management of the MHV and its tributaries in right lobe LDLT

critical in LDLT. In addition to use of optimal vein grafts, another technique for creating a common outflow tract using venoplasties of the graft and recipient hepatic veins has recently been introduced.[34] Lo et al recommended this technique as a standard one in right lobe grafts with the MHV. This technique was used successfully by this group in 8 cases without interposition graft. All the liver grafts showed immediate function, and no hepatic venous outflow obstruction was observed.[35] During the operation, the adjustment of the shape, exact length, orientation, and diameter of the anastomosed veins was difficult, and incompatible anastomosis usually led to the obstruction of venous outflow. Hepatic venoplasty can minimize these difficulties. The common orifice of the hepatic veins in the graft after the venoplasty can maintain its size and shape because of the support from the surrounding liver substance. This orifice can be directly or indirectly anastomosed using a shorter interpositional graft to an opening of similar size and shape in the inferior vena cava, which can always be tailored to match the orifice.[35] This technique can be performed when the reconstruction of the MHV is technically difficult or there is no optimal vein graft. It can obviate the possibility of obstruction because of kinking or misalignment. As a result, hepatic venoplasty can simplify the operation and guarantee excellent venous drainage.[35, 36] It can be used as an effective technique for hepatic venous reconstruction.

Graft size Graft size is known to be a major risk factor and one of the key elements[37] in living donor liver transplantation. Size disparity of the graft, which is responsible for small-for-size syndrome,[2] usually leads to septic complications and high mortality.[38] To avoid a "size disparity" graft, right lobe grafts have been increasingly used. However, larger grafts will raise the risks for the living donor and bring about an important ethical issue. Several studies have been attempted to solve the problem of determining the optimal graft size for successful right lobe living donor liver transplants. Seaman[8] proposed the practical option of more than 40% of expected recipient ideal liver volume or more than 1% of graftto-recipient weight ratio is transplantation of a full right lobe. Whereas Marcos et al[39] indicated in their study that a graft-to-recipient weight ratio of at least 0.8% was a minimum requirement. On the other hand, harvesting a larger graft puts the donor at high risk, as Lo et al proved in their research.[40] Some researchers[41] found that larger graft was not always

required (less than 10% of the recipients needed an extended right graft). Tanaka et al[7] reported the estimated remnant of the native liver was 45% of the whole liver, and most donors retained more than 35% of the original liver mass in their series of initial right lobe living donor liver transplantations. They recommended the rejection of a donor if the remnant liver volume is below 30%.[1] For the problem of determining the optimal graft size, further concern should be focused on the ability to resect a graft of adequate size without subjecting the donor to undue risk.

Prospects Adult-to-adult LDLT using a right lobe graft seems to be a natural consequence of the accumulation of experience and has further extended the limitation caused by the size disparity. For solving the congestion problem of right paramedian sector, using right liver grafts with the MHV trunk (extended right lobe grafts) or performing the reconstruction of MHV tributaries in modified right lobe grafts appears to be effective. This technique with successful management of the MHV and its tributaries in right lobe LDLT provides a functioning liver mass, and helps to improve the results of the patients. The experience may also be helpful in splitting cadaver livers, which can minimize the need for living donation.[7] Further clinical studies are urgently needed to reduce the donor risk and the potential complication in patients, and make technical innovation in these surgical procedures. Funding: This study was supported by a grant from the National Key Basic Research Program (973) of China (No. 2003 CB515501), and Important Project from Science and Technology Department of Zhejiang Province (No. 021103699). Ethical approval: Not needed. Contributors: YPF wrote the article under the supervision of WJ and ZSS. ZSS is the guarantor. Competing interest: No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

References 1    Tanaka K, Yamada T. Living donor liver transplantation in Japan and Kyoto University: what can we learn? J Hepatol 2005;42:25-28. 2    Pan GD, Yan LN. Problems in adult living donor liver transplantation using the right hepatic lobe. Hepatobiliary Pancreat Dis Int 2006;5:345-349. 3    Lo CM, Fan ST, Liu CL, Wei WI, Lo RJ, Lai CL, et al. Adult-to-adult living donor liver transplantation using

Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com • 361

Hepatobiliary & Pancreatic Diseases International

extended right lobe grafts. Ann Surg 1997;226:261-269; discussion 269-270. 4    K im DG, Moon IS, Kim SJ, Lee YJ, Lee MD. Effect of middle hepatic vein reconstruction in living donor liver transplantation using right lobe. Transplant Proc 2006;38: 2099-2101. 5    Ger R. Surgical anatomy of the liver. Surg Clin North Am 1989;69:179-192. 6    Yamaoka Y, Washida M, Honda K, Tanaka K, Mori K, Shimahara Y, et al. Liver transplantation using a right lobe graft from a living related donor. Transplantation 1994;57: 1127-1130. 7    T  anaka K, Kobayashi Y, Kiuchi T. Current status of living donor liver transplantation in adults. Curr Opin Organ Transpl 2000;5:74-79. 8    Seaman DS. Adult living donor liver transplantation: current status. J Clin Gastroenterol 2001;33:97-106. 9    L  ee S, Park K, Hwang S, Kim K, Ahn C, Moon D, et al. Anterior segment congestion of a right liver lobe graft in living-donor liver transplantation and strategy to prevent congestion. J Hepatobiliary Pancreat Surg 2003;10:16-25. 10 A  scher NL, Lake JR, Emond JC, Roberts JP. Liver transplantation for fulminant hepatic failure. Arch Surg 1993;128:677-682. 11 Lo CM, Fan ST, Liu CL, Lo RJ, Lau GK, Wei WI, et al. Extending the limit on the size of adult recipient in living donor liver transplantation using extended right lobe graft. Transplantation 1997;63:1524-1528. 12 T  rotter JF, Wachs M, Everson GT, Kam I. Adult-to-adult transplantation of the right hepatic lobe from a living donor. N Engl J Med 2002;346:1074-1082. 13 F  an ST, Lo CM, Liu CL, Wang WX, Wong J. Safety and necessity of including the middle hepatic vein in the right lobe graft in adult-to-adult live donor liver transplantation. Ann Surg 2003;238:137-148. 14 F  an ST, De Villa VH, Kiuchi T, Lee SG, Makuuchi M. Right anterior sector drainage in right-lobe live-donor liver transplantation. Transplantation 2003;75(3 Suppl): S25-S27. 15 W  achs ME, Bak TE, Karrer FM, Everson GT, Shrestha R, Trouillot TE, et al. Adult living donor liver transplantation using a right hepatic lobe. Transplantation 1998;66:1313-1316. 16 M  arcos A, Fisher RA, Ham JM, Shiffman ML, Sanyal AJ, Luketic VA, et al. Right lobe living donor liver transplantation. Transplantation 1999;68:798-803. 17 Y  amamoto H, Maetani Y, Kiuchi T, Ito T, Kaihara S, Egawa H, et al. Background and clinical impact of tissue congestion in right-lobe living-donor liver grafts: a magnetic resonance imaging study. Transplantation 2003; 76:164-169. 18 L  ee SG. Asian contribution to living donor liver transplantation. J Gastroenterol Hepatol 2006;21:572-574. 19 C  escon M, Sugawara Y, Sano K, Ohkubo T, Kaneko J, Makuuchi M. Right liver graft without middle hepatic vein reconstruction from a living donor. Transplantation 2002;73:1164-1166. 20 L  ee KW, Lee DS, Lee HH, Joh JW, Choi SH, Heo JS, et al. Interpostion vein graft in living donor liver transplantation. Transplant Proc 2004;36:2261-2262. 21 d  e Villa VH, Chen CL, Chen YS, Wang CC, Lin CC, Cheng

22

23 24

25

26

27

28

29

30

31 32

33

34

35

36

YF, et al. Right lobe living donor liver transplantationaddressing the middle hepatic vein controversy. Ann Surg 2003;238:275-282. Kaneko T, Kaneko K, Sugimoto H, Inoue S, Hatsuno T, Sawada K, et al. Intrahepatic anastomosis formation between the hepatic veins in the graft liver of the living related liver transplantation: observation by Doppler ultrasonography. Transplantation 2000;70:982-985. Lee S, Park K, Hwang S, Lee Y, Choi D, Kim K, et al. Congestion of right liver graft in living donor liver transplantation. Transplantation 2001;71:812-814. Maetani Y, Itoh K, Egawa H, Shibata T, Ametani F, Kubo T, et al. Factors influencing liver regeneration following living-donor liver transplantation of the right hepatic lobe. Transplantation 2003;75:97-102. Sano K, Makuuchi M, Miki K, Maema A, Sugawara Y, Imamura H, et al. Evaluation of hepatic venous congestion: proposed indication criteria for hepatic vein reconstruction. Ann Surg 2002;236:241-247. K  ubota T, Togo S, Sekido H, Shizawa R, Takeda K, Morioka D, et al. Indications for hepatic vein reconstruction in living donor liver transplantation of right liver grafts. Transplant Proc 2004;36:2263-2266. Gyu Lee S, Min Park K, Hwang S, Hun Kim K, Nak Choi D, Hyung Joo S, et al. Modified right liver graft from a living donor to prevent congestion. Transplantation 2002;74:54-59. Mizuno S, Iida T, Yagi S, Usui M, Sakurai H, Isaji S, et al. Impact of venous drainage on regeneration of the anterior segment of right living-related liver grafts. Clin Transplant 2006;20:509-516. Sugawara Y, Makuuchi M, Sano K, Imamura H, Kaneko J, Ohkubo T, et al. Vein reconstruction in modified right liver graft for living donor liver transplantation. Ann Surg 2003;237:180-185. Cattral MS, Greig PD, Muradali D, Grant D. Reconstruction of middle hepatic vein of a living-donor right lobe liver graft with recipient left portal vein. Transplantation 2001;71:1864-1866. W  u H, Yan LN, Zhao JC, Li B, Zeng Y, Wen TF, et al. Using vein grafts in living donor liver transplantation. Zhonghua Gan Zang Bing Za Zhi 2006;14:927-929. Hashimoto T, Sugawara Y, Kishi Y, Akamatsu N, Matsui Y, Kokudo N, et al. Superior vena cava graft for right liver and right lateral sector transplantation. Transplantation 2005;79:920-925. Sugawara Y, Makuuchi M, Akamatsu N, Kishi Y, Niiya T, Kaneko J, et al. Refinement of venous reconstruction using cryo Linkspreserved veins in right liver grafts. Liver Transpl 2004;10:541-547. de Villa VH, Chen CL, Chen YS, Wang CC, Wang SH, Chiang YC, et al. Outflow tract reconstruction in living donor liver transplantation. Transplantation 2000;70:16041608. L  o CM, Fan ST, Liu CL, Wong J. Hepatic venoplasty in living-donor liver transplantation using right lobe graft with middle hepatic vein. Transplantation 2003;75:358-360. Liu CL, Zhao Y, Lo CM, Fan ST. Hepatic venoplasty in right lobe live donor liver transplantation. Liver Transpl 2003;9:1265-1272.

362 • Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com

Management of the MHV and its tributaries in right lobe LDLT

37 W  ang WX, Fan ST. Live donor liver transplantation in adults: graft size, related anatomical anomaly and imaging evaluation of donor. Hepatobiliary Pancreat Dis Int 2002;1:14-17. 38 K iuchi T, Kasahara M, Uryuhara K, Inomata Y, Uemoto S, Asonuma K, et al. Impact of graft size mismatching on graft prognosis in liver transplantation from living donors. Transplantation 1999;67:321-327. 39 Marcos A, Ham JM, Fisher RA, Olzinski AT, Posner MP. Single-center analysis of the first 40 adult-to-adult living

donor liver transplants using the right lobe. Liver Transpl 2000;6:296-301. 40 Lo CM, Fan ST, Liu CL, Yong BH, Chan JK, Wong J. Increased risk for living liver donors after extended right lobectomy. Transplant Proc 1999;31:533-534. 41 Marcos A. Right lobe living donor liver transplantation: a review. Liver Transpl 2000;6:3-20. Received May 18, 2007 Accepted after revision July 17, 2007

A man who is never satisfied with himself and whom therefore nobody can please. —Johann Wolfgang con Goethe Hepatobiliary Pancreat Dis Int，Vol 6，No 4 • August 15，2007 • www.hbpdint.com • 363