小型猪原位肝移植模型的建立与评价

目的 探讨建立放弃静脉转流的小型猪原位肝移植模型的可行性。方法 选用广西巴马小型猪(3-6月龄,8-11kg)为实验动物,共实施原位肝移植10例次。供体肝脏游离、冷灌注、切取、修整以及UW保存按常规方法进行。受体术中肝脏游离后夹闭肝上、肝下下腔静脉和门静脉并切除受体肝脏,各血管断端与供肝相应血管进行端端吻合,肝上下腔静脉和门静脉吻合完毕即开放肝脏血流,在此过程中未使用静脉转流,此后吻合肝动脉、胆管。结果 本组10例次肝移植手术后一周存活率90％(9/10),无肝期时间31.3±2.67min,无肝期血压显著下降(MAP4.5±1.58kPa)但肝血流开放后能较快恢复并渐趋平稳。结论 本组结果表明,非静脉转流条件下的小型猪肝移植模型是一操作方便、易于复制同时又具有较好重复性和稳定性的大动物肝移植模型,能应用于肝移植的系列实验研究。     

小型猪原位肝移植模型的建立:体外静脉转流的重要性及两种被动静脉转流方式的比较

目的 建立巴马小香猪原位肝移植模型,探究体外静脉转流对于猪肝移植模型建立的重要性.方法 实施以巴马小香猪为实验对象的原位肝移植共30例.供体肝脏游离、灌注、切取以及保存按常规方法进行.受体术中置入左侧髂外静脉、脾静脉/门静脉和左侧颈浅静脉"Y"形插管,用作无肝期的静脉-静脉转流.受体术中肝脏游离完成后阻断门静脉,肝上、肝下下腔静脉后开放左侧髂外静脉、脾静脉/门静脉-左侧颈浅静脉转流.血管和胆道均采取端端吻合.结果 前6例未采取体外静脉-静脉转流的原位肝移植手术的受体术中全部死亡,存活率为0.0%(0/6);采用脾静脉-颈浅静脉转流方式的受体术中存活率为57.1%(8/14),而采用门静脉-颈浅静脉转流方式的受体术中存活率为100.0%(10/10),具有显著性差异(P＜0.05).原位肝移植手术时间平均为6.5 h,受体无肝期平均为(33±12)min.供肝热缺血时间平均为2 min,冷缺血时间平均为130 min.结论 采用左侧髂外静脉、门静脉主干-左侧颈浅静脉转流方式的巴马小香猪原位肝移植模型是具有可重复性好,需要的设备少,更加经济,疗效好,是比较理想的猪肝移植模型.可作为肝移植系列研究的平台.     

Retransplantation of the liver in the rat

A successful technique of liver retransplantation in the rat is described. Heterotopic nonauxiliary liver engraftment of a whole liver using cuffed anastomoses is the primary transplant procedure. The graft is implanted in the right hypochondrium and is revascularized by a portal end-to-end anastomosis. Venous drainage is via an end-to-side anastomosis between the donor infrahepatic vena cava and recipient right renal vein. The graft suprahepatic vena cava is ligated. Biliary drainage is achieved by a double stent anastomosis of the biliary ducts. Total parenchymectomy of the recipient's liver is completed leaving intact the intrahepatic and suprahepatic vena cava. Retransplantation in the orthotopic position can thus be attempted, after removal of the first graft, by cuffed anastomoses between the donor and recipient portal veins, infrahepatic vena cava and a double stent anastomosis of the common bile ducts. Anastomosis between the donor and recipient suprahepatic vena cava is completed with a 7/0 Prolene running suture. In the first group of operations (n = 6), a three week survival rate of 50% after retransplantation was obtained. Using the technical lessons of these preliminary cases, 80% of the second group of operations (n = 5), were successful in the long term. Utilization of this new technique may allow further investigations in different fields of research dealing with liver surgery and transplantation. © 1993 Wiley-Liss Inc.     

猪辅助性部分肝移植模型制作及比较

目的建立猪的辅助性部分肝移植模型,观察其肝功能和术中血流动力学变化。方法 24头健康良种家猪,体质量23-30 kg,被随机分为供体(n=12)和受体(n=12)。气管插管 全麻,硫喷妥钠静脉维持。移植前切除受体肝左叶,供肝右叶作为植入肝。预实验2例行经体位转流的原位辅助性部分肝移植,对照组(5例)行简易转流下的原位辅助性部分肝移植。模型组(5例)行异位辅助性部分肝移植, 供肝被植入受体肝下间隙,供肝肝上下腔静脉与受体肝下下腔静脉端侧吻合,供肝门静脉与受体门静脉行端侧吻合,供肝肝动脉与受体脾动脉行端端吻合。供肝胆总管置管外引流。结果预实验中行体位静脉转流的原位辅助性部分肝移植的2例受体在肝上下腔静脉阻断后很快陷入血流动力学紊乱死亡。5例行简易静脉转流的原位辅助性部分肝移植的受体,2例在24 h内死亡,1例28 h,2侧超过48 h。而模型组受体 5例中有4例存活超过24 h。AST,ALT指标手术开始至术后24 h呈持续升高。模型组术中血流动力学较其他组稳定。结论该辅助性肝移植模型简明易建且具有不需静脉转流等优点,为研究辅助性部分肝移植原肝和供肝功能及血流变化提供了理想的平台。     

Rat liver transplantation for total vascular reconstruction, using a suture method

We developed a novel protocol for rat orthotopic liver transplantation (OLT), using a suture method to establish hepatic artery flow. After determining that early inferior vena cava (IVC) unclamping maintained better circulation compared with the portal vein (PV) using porto-systemic shunted recipients, we developed a rat OLT model with total vascular reconstruction using a suture method. After connecting the suprahepatic IVC, the infrahepatic IVC was anastomosed, using a running suture method. IVC circulation was established immediately. The PV was anastomosed without intestinal congestion, using porto-systemic shunted recipients. The aortic conduit, including the donor celiac and hepatic artery, was anastomosed to the recipient abdominal aorta end-to-side. Eight of 11 OLT cases (72.7%) survived indefinitely. Biliary connection was achieved using a one-stent method. Three cases died 3-5 days postoperatively. Hepatic angiography showed good patency. The graft liver was histologically normal in long-surviving rats.     

A rare case of complex vascular reconstruction in liver transplantation.

Abnormalities of recipient or donor vascular structures are associated with reconstructive difficulties in liver transplantation. A patient with thrombosis of the right hepatic vein and associated stricture of the inferior vena cava (IVC), portal vein thrombosis and multiple aberrant arteries underwent orthotopic liver transplantation. The donor's suprahepatic IVC was anastomosed to the recipient's intrathoracic IVC. The portal vein flow was restored by venous graft interposition, while the arterial flow was ensured by interposing an iliac arterial graft anastomosed to the infrarenal aorta. In conclusion, graft function remains excellent more than 5 years postoperatively.     

Supraceliac aortic clamping during the anhepatic phase of experimental orthotopic liver transplantation.

BACKGROUND: The pig tolerates simultaneous clamping of the liver pedicle and inferior vena cava poorly, so venovenous bypass has to be used during the anhepatic phase of experimental orthotopic liver transplantation (OLT). The aim of this work is to assess whether clamping of the supracoeliac aorta during the anhepatic phase (AP) of experimental OLT in pigs allows transplantation in stable hemodynamic conditions. METHODS: Fourteen pigs (weight, 16 to 18 kg) received whole liver grafts from 14 age-matched donors and were subsequently divided into two groups: group I, OLT without venovenous bypass during the AP, group II, OLT with supracoeliac aortic clamping during the AP. Variables analyzed were cardiac output (CO) and related variables, mean systemic arterial pressure (MAP), mixed venous oxygen saturation (SvO2), hepatic artery and portal vein blood flow, systemic and hepatic O2 supply and uptake (SDO2, SVO2, HDO2, HVO2, respectively), liver enzymes, glucose, creatinine, and electrolytes. RESULTS: In group I, CO, MAP, and SvO2, decreased during the AP (anhepatic) in comparison with baseline (preanhepatic) values (CO, 3.60+/-0.74, preanhepatic, v. 1.21+/-0.25 L x min(-1), anhepatic; P<.05. MAP, 97+/-12, preanhepatic, v. 43+/-17 mm Hg, anhepatic; P<.05. SvO2, 91.6+/-5.6, preanhepatic v. 70.0+/-12.5%, anhepatic; P<.05), and SDO2/SVO2 increased by 16% (preanhepatic) to 33% (anhepatic; P<.05). In group II, CO decreased during the anhepatic phase by only 21% (3.82+/-0.81, preanhepatic, v. 3.07+/-0.99 L x min(-1), anhepatic; not significant), the MAP increased significantly (100+/-8, preanhepatic, v. 135+/-4 mm Hg, anhepatic; P<.05), and SVO2, SDO2, SVO2, and SDO2/SVO2 remained unchanged. After revascularization, none of these variables differed significantly between groups, and levels of liver enzymes, glucose, creatinine, urea, and electrolytes were similar in both groups, both before and aftertransplantation. CONCLUSIONS: Experimental OLT can be carried out in pigs without venovenous bypass, but it leads to severe hemodynamic disturbances. Clamping of the supraceliac artery during the AP is well tolerated and results in excellent hemodynamic stability, so it may prove to be a useful technique in liver transplantation in animals, such as dogs or pigs, that do not tolerate simultaneous clamping of the liver pedicle and inferior vena cava as well as human beings.     

Novel magnetic rings for rapid vascular reconstruction in canine liver transplantation model

OBJECTIVE: Magnetic rings were used for rapid vascular reconstruction in a canine liver transplantation model. MATERIALS AND METHODS: Thirty-two adult mongrel dogs weighing 13 to 16 kg were randomly selected as donors or recipients of transplantations. The recipients were randomly divided into two groups: group A (n = 10) had magnetic rings used for vascular reconstruction without venovenous bypass; group B (n = 6) had vascular reconstruction performed by continuous suturing with splenojugular venovenous bypass. RESULTS: In group A, the entire operative period was 3.24 +/- 0.49 hours, the durations of clamping the portal vein and the infrahepatic vena cava of the recipient were 5.89 +/- 2.27 minutes and 3.89 +/- 0.73 minutes, respectively. In group B, the entire operative period was 4.12 +/- 0.51 hours with the duration of clamping portal vein and infrahepatic vena cava, 28.33 +/- 6.04 minutes and 12.16 +/- 3.72 minutes (P < .01 vs group A). In group A, mean arterial pressure dropped during the anhepatic phase but recovered quickly after reperfusion. The fluid infusion was about 730.56 +/- 50.56 mL in the group A and a pressor agent was unnecessary. In group B, blood pressure dropped during the anhepatic phase and slowly recovered. The fluid infusion was about 2241.67 +/- 390.78 mL and a pressor agent was used to maintain the blood pressure of the recipient. No twist or thrombus was discovered in the anastomoses group A and the endothelium at the site of anastomosis was entire. In group B, errhysis was common in the anastomotic stomas. Nine of 10 dogs in group A survived more than 3 days, the longest being 8 days, whereas four of the six dogs in group B survived less than 3 days. CONCLUSION: The results showed that the anhepatic time was significantly shortened (about 5.89 +/- 2.27 minutes) in group A compared with group B and venovenous bypass was unnecessary. Magnetic rings could be used for rapid vascular reconstruction in canine liver transplantation model. The long-term results of this procedure should be clarified before it is applied in clinical practice in the future.     

Evaluation, operative management, and outcome after liver transplantation in children with biliary atresia and situs inversus.

INTRODUCTION: Biliary atresia, a common indication for liver transplantation, can be associated with situs inversus. Our experience with liver transplantation in children (n = 6) was reviewed retrospectively. PATIENTS AND METHODS: Preoperative duplex sonography, computerized tomography, and visceral angiography were obtained. Vascular anomalies identified included preduodenal portal vein (6/6), interrupted inferior vena cava (5/6), and aberrant hepatic artery (4/6). RESULTS: The liver graft was placed in a midline position. Venous continuity was achieved by donor suprahepatic inferior vena cava to recipient hepatic cloaca and direct end-to-end portal anastomosis. The donor infrahepatic inferior vena cava was oversewn. Arterial continuity was restored using either a direct branch-patch anastomosis (3/6) or a supraceliac aortic interposition graft (3/6). In retrospect, preoperative diagnostic work-up was noncontributory and outcome was not complicated by pre-existing situs inversus. CONCLUSION: Situs inversus in liver recipients requires operative technical modifications, but does not change outcome. Furthermore, extensive preoperative work-up should be avoided.     

自体原位肝移植逆行灌注法对大鼠急性肾损伤的影响

目的探讨自体原位肝移植术中经下腔静脉逆行灌注对大鼠肾功能的影响,为临床肝移植应用经下腔静脉逆行灌注法提供实验依据。方法 60只自体原位肝移植大鼠随机分为逆行灌注组、门静脉灌注组与假手术组各20只。前两组建立自体肝移植模型,其中逆行灌注组采用经下腔静脉逆行灌注法,先开放下腔静脉,再开放门静脉,最后开放肝动脉。门静脉灌注组采用常规经门静脉正向灌注法,先开放门静脉,再开放下腔静脉,最后开放肝动脉。假手术组开腹后游离肝门处门静脉、肝动脉及肝上、下下腔静脉,不予阻断,17min后关腹。分别检测3组术前1h、术后1h、8h及术后1d、5d的血清肌酐(Scr)、血尿素氮(BUN)水平;无肝期结束后1h、8h、1d取左肾组织行光镜检查观察肾组织病理形态学变化。结果术前1h,各组肾功能指标比较差异均无统计学意义(均为P>0.05);与假手术组比较,逆行灌注组、门静脉灌注组术后1h、8h及1d的Scr、BUN水平显著增高,而且逆行灌注组上述两指标明显低于门静脉灌注组(均为P<0.05),但术后5d3组比较差异均无统计学意义(均为P>0.05)。无肝期结束后1h,逆行灌注组和门静脉灌注组肾组织病理学检查发现肾间质充血,8h出现明显的肾小管上皮细胞水肿及肾间质充血,逆行灌注组明显轻于门静脉灌注组;无肝期结束后1d两组肾组织损伤呈现好转趋势,且逆行灌注组明显优于门静脉灌注组。结论自体原位肝移植术中实施逆行灌注可减轻大鼠急性肾损伤,改善大鼠早期肾功能。     

Hemodynamic changes with initiation of veno-venous bypass in orthotopic liver transplant patients

Removal of the liver to start the anhepatic stage of liver transplantation requires cross-clamping of the portal vein, inferior vena cava, and hepatic artery. Adverse effects occur from engorged splanchnic beds and decreased venous return. A veno-venous bypass from the inferior vena cava and portal vein to the axillary vein is used in an attempt to ameliorate these changes. The purpose of this study was to evaluate the effect of institution of veno-venous bypass on hemodynamics. Eight randomly selected adult patients undergoing orthotopic liver transplantation had general anesthesia induced with thiamylal and maintained with nitrous oxide and isoflurane. Cardiopulmonary data and arterial and mixed venous blood gases were measured prospectively using radial artery and pulmonary artery catheters. Measurements were taken under four conditions: (1) 10 minutes before bypass; (2) after partial bypass (vena cava to the axillary vein); (3) after partial bypass with portal vein clamping; and (4) after full bypass (vena cava and portal vein to the axillary vein). Statistically significant changes seen were a 22% decrease in cardiac output and a 47% increase in systemic vascular resistance (SVR). Bypass flow was lower than predicted. Venovenous bypass ameliorates, but does not fully prevent, the reduction of cardiac output and rise in SVR seen with initiation of the anhepatic stage. However, bypass does prevent the hypotension experienced during cross-clamping and for these reasons should be used routinely.     

大鼠原位肝移植模型的手术操作技巧探讨

目的 建立一个稳定的大鼠原位肝移植模型，探讨其手术技巧。方法在Kamada“二袖套法”的基础上进行改良。供体改经腹主动脉进行肝脏冷灌注；肝上下腔静脉用连续缝合法吻合，门静脉和肝下下腔静脉用袖套法吻合．胆总管采用单管内支架胆管端端吻合法。结果共施行大鼠原位肝移植140例，无肝期平均11min．手术成功率为97％,大鼠1周存活率为95％。结论改良的两袖套法具有操作简便、无肝期短、手术成功率高、大鼠术后存活时间长的优点，是大鼠原位肝移植的理想术式。娴熟细致的外科操作、受体无肝期的长短是决定动物存活的关键。     

Perioperative cytokines during orthotopic liver transplantation without venovenous bypass

Since most of studies investigating cytokine levels during human orthotopic liver transplantation used venovenous bypass (VVB), it may be difficult to distinguish between the increase in proinflammatory mediators induced by VVB, by ischemia-reperfusion injury or by splanchnic venous congestion in the anhepatic phase. The goal of this investigation was to assess the levels of interleukin-6 (IL-6) and soluble interleukin-2 receptors (sIL-2r) during OLT procedures routinely performed without VVB. PATIENTS AND METHODS: Twenty-one consecutive patients underwent OLT with cross clamping of the inferior caval vein without VVB. Soluble IL-2r concentrations were measured by means of luminescence enzyme immunometric assay and IL-6 by means of a sequential immunometric assay. Time points (TP) of sampling were before induction of anesthesia (TP1), after cross-clamping of the inferior vena cava (TP2), 15 minutes after reperfusion (TP3), and 24 hours after the transplant procedure (TP4). RESULTS: Soluble IL-2r increased significantly 24 hours after transplantation (P =.02) compared to TP1, TP2, and TP3. IL-6 increased significantly during the anhepatic period (TP2 vs TP1, P =.003) and again in the reperfusion period (TP2 vs TP3, P =.002). Twenty-four hours after surgery IL-6 declined significantly (TP3 vs TP4, P =.001), but remained significantly higher (P = 0.04) compared to TP1. Furthermore, we examined the relative changes (DeltaTP %) in perioperative levels of cytokines compared with those previously published in studies using VVB. We observed higher values of DeltaTP % of IL-6 in TP2 and TP4 among our group of patient without VVB. The data on sIL-2r were similar, suggesting no major effects of the operative technique on sIL-2r levels. CONCLUSION: The two interleukins showed different perioperative trends. Our data suggest that cross clamping contributes more to cell activation, namely, increased release of IL-6 in the anhepatic phase than the use of VVB. However, no major differences were observed during the reperfusion period. The extent of clinical effect on graft function of higher IL-6 levels in the anhepatic period among recipients not supported with VVB remains to be clarified.     

大鼠原位肝移植模型的建立及术式改进

目的探讨用双袖套法建立大鼠原位肝移植模型的手术改进方法. 方法在Kamada等的袖套法吻合血管的基础上进行改进,供体改经腹主动脉进行肝脏冷灌注,肝上下腔静脉用缝合法吻合,门静脉和肝下下腔静脉用袖套法吻合,胆总管采用单管内支架胆管端端吻合下进行原位肝移植360例(次). 结果施行大鼠原位肝移植其供体手术时间(31.2±5.0)分钟,供肝修整时间(12.0±3.0)分钟,受体手术时间(45.0±5.5)分钟,无肝期(20.0±2.5)分钟,手术死亡31例,其中出血12例,肝下下腔静脉血栓8例,肝上下腔静脉回流不畅7例,袖套扭转或脱落4例.术后成活2天以上329例,成活率为91.4%.非干预组(非药物治疗组)1周存活率达86.5%. 结论改进的大鼠原位肝移植术操作简便,手术成功率高,可作为肝移植实验可靠、稳定的动物模型.     

Auxiliary liver transplantation in acute liver failure in the rat – an illustrated description of a new surgical approach

INTRODUCTION: To investigate auxiliary liver transplantation successfully in rats suffering from acute liver failure, we developed a new surgical approach. METHODS: A 70% hepatectomized liver graft was implanted into the right upper quadrant of the abdomen. The donor portal vein was anastomosed with the recipient's right renal artery using the splint technique. The donor infrahepatic vena cava was attached onto the recipient vena cava end to side. The bile duct was implanted into the duodenum.     

Surgical Techniques of Allogeneic Liver Transplantation in a Nonhuman Primate Model

Herein, we report our experience of performing allogeneic orthotopic liver transplantation (LT) in nonhuman primates. We designed an allogeneic ABO-compatible orthotopic LT model in monkeys in a manner similar to that used in humans. We applied almost the same surgical procedures used for human conventional deceased donor LT. A total of 6 monkeys underwent allogeneic LT. One cynomolgus monkey aged 45 months (3.4 kg) and 5 rhesus macaque monkeys aged 50.2 ± 14.8 months (5.40 ± 0.33 kg) were used as recipients. In the donor surgery, the liver was perfused in situ through the aorta using cold histidine-tryptophan-ketoglutarate solution. The portal vein (diameter, 5–10 mm), supra- and infra-hepatic inferior vena cava (IVC) (diameter, 12–15 mm), and common bile duct (diameter, 1.5–3.0 mm) were dissected out. The hepatic artery was kept in continuity with the celiac trunk and abdominal aorta up to the iliac bifurcation (diameter, 5–6 mm). The mean graft weight was 102.0 g (94.8–111.0 g). Recipient surgery was conducted in parallel. After recipient hepatectomy, the graft was implanted. The suprahepatic IVC and portal vein were anastomosed to those of the graft. After reperfusion, the infrahepatic IVC was anastomosed. The aorta conduit of the graft was anastomosed to the infrarenal aorta of the recipient in a retrocolic end-to-side manner. Biliary reconstruction was performed in a duct-to-duct anastomosis with cholecystectomy. Mean operative time was 107.0 minutes for donor and 198.2 minutes for recipient. There was one operative death due to unknown cause. In conclusion, for allogeneic orthotopic LT in nonhuman primate model, we can apply almost the same procedure used for human conventional deceased donor LT in a similar manner.     

Orthotopic allotransplantation of the canine liver; a simplified technic with hypothermia

A simplified technique of the liver transplantation under hypothermia has been studied in dog. An immersion hypothermia was used in both the donor and the recipient. The temperature of the graft at excision was lowered to 20 degrees C with supplemental use of topical cooling. The temperature of the recipient was lowered at 27 degrees C when the transplantation was attempted. Chlorpromazine and dopamine were employed beneficially in hypothermia. No perfusion or irrigation of the graft was performed. The use of heparin was avoided. Anastomoses were carried out in turn of the proximal vena cava, portal vein, distal vena cava and the hepatic artery with a stem shaped aorta. Reperfusion was established after the completion of anastomosis between the proximal vena cava and portal vein. The anhepatic phase of the recipient was uneventfully lasted without heparinization. All dogs, 5 out of 11 without early surgical troubles survived more than 5 days. Immunosuppressive therapy was not employed except one which died of pneumonia on the 19th postoperative day. Histologically, these dogs were free from ischemic injury and/or thrombotic lesion throughout transplantation procedure.     

A simple method of orthotopic liver transplantation in dogs.

Orthotopic liver transplantations were performed by one team in 18 dogs using a cuff method to anastomose the portal vein, the suprahepatic vena cava and the infrahepatic vena cava without external or internal shunts. Total and warm ischemic times of donor liver averaged 124 and 32 minutes, respectively. The average occlusion time of the portal vein and the infrahepatic vena cava were 9.7 and 13.9 minutes, respectively. During this time, uncontrolled hypotension, petechiae or hemorrhagic enterogastritis did not develop. Sixteen of 18 dogs survived more than five days, and five dogs lived more than three weeks. The cause of death was not related to the cuff method in any instance. This approach proved to be a technically simple and satisfactory procedure.     

Liver transplantation in an adult patient with situs inversus: a case report and overview of the literature

Liver transplantation (OLT) in an adult with situs inversus (SI) is extremely rare and considered a contraindication because of the anatomic difficulties. A 45-year-old male patient with complete SI, suffering from progressive hepatic failure secondary to hepatolithiasis, obstructive jaundice, and liver cirrhosis, underwent transplantation in July 2004. Preoperatively the liver anatomy was determined by computed tomography scan, three-dimensional liver reconstruction, and angiography. OLT was performed using a modified piggyback technique, the donor right lobe was rotated 45 degrees to the left, making the donor left lobe point into the left paracolic sulcus and the donor right lobe in the recipient hepatic fossa. The donor's suprahepatic vena cava was sewn end to side to the recipient vena cava, and the infrahepatic vena cava oversewn. The patient recovered uneventfully, and transplant perfusion and function were stable at a follow-up of 40 months. The present study showed OLT in adult patients with SI to be feasible. The knowledge of exact anatomy, meticulous preoperative planning, and optimization of the recipients condition are essential.     

Does adult liver transplantation without venovenous bypass result in renal failure?

Thirty-eight adult orthotopic liver transplant recipients were studied to compare renal hemodynamics and renal function with (17 patients) and without (21 patients) venovenous bypass. Bypass was used when mean arterial blood pressure decreased by greater than 30% or cardiac index decreased by greater than 50%, or both, during a 5-min trial of clamping of the suprahepatic and infrahepatic vena cava and portal vein. Intraoperative measurements were performed 2 h after induction of anesthesia, 10 min before the end of the anhepatic phase, and 2 h after cava unclamping. During the anhepatic stage, renal perfusion pressure decreased significantly in the group with no bypass (79 +/- 20 vs 60 +/- 17 mm Hg, P less than 0.05) (mean +/- SD), whereas it remained unchanged in the group with bypass (77 +/- 14 vs 74 +/- 16 mm Hg, NS); urinary output was not modified in the bypass group, whereas it decreased significantly in the group with no bypass compared with the dissection phase (0.7 +/- 0.6 vs 1.7 +/- 2.0 mL.kg-1.h-1, P less than 0.05). However, during the postreperfusion phase, urinary output was similar in both groups and was more when compared with the dissection phase (P less than 0.05). Serum creatinine level was increased in both groups on the third postoperative day, but no difference occurred between the groups (bypass group 107 +/- 49 mmol/L; nonbypass group 126 +/- 95 mmol/L). No patient required dialysis in either group in the postoperative period. This study suggests that in patients without preoperative renal failure and who tolerate the trial of clamping well, venovenous bypass is not required to maintain postoperative renal function after liver transplantation.