A new bioabsorbable material for rat vascular cuff anatomosis: establishment for the long-term orthotopic liver transplantation model.

Rat vascular anastomosis was performed using a newly synthesized bioabsorbable material (LA-GA copolymer) cuffs and the ordinary polyethylene cuffs. The LA-GA copolymer cuff which anastomosed the portal vein and the inferior vena cava were patent and developed no collateral veins even after 6 months, keeping the transplanted liver normal. By contrast, the polyethylene cuff anastomosed portal vein was completely occluded and the collateral veins were highly developed, with the transplanted liver showing the fatty degeneration of hepatocytes and numerous regenerative nodules. It is concluded that the LA-GA copolymer cuff is a suitable material for the short and long term study of rat orthotopic liver transplantation.     

Heterotopic auxiliary liver transplantation with portal flow. Gradual development of the collateral circulation

One of the causes of auxiliary liver transplantation failure is the inter-liver competition between the host liver and the graft for the hepatotrophic factors of the portal blood. We have developed an experimental model of heterotopic partial (30%) liver isotransplant using Wistar rats so as to study this competition. Splenoportography and dissection demonstrate the existence of collateral circulation. The collaterals at 90 days post-transplant (PT) consisted of veins from the portal vein to the host liver (PR), paraesophageal veins (PE) and splenorenal veins (SR). At 60 days P.T., PR and SR veins but not PE ones appeared, and at 30 days P.T., there were only PR veins. Graft atrophy at 90 days P.T. was associated with a severe degree of bile duct proliferation. The gradual development of portal hypertension causes porto-systemic collateral circulation and the graft loses the portal hepatotrophic factors. The late development of the portal hypertension and the biliary proliferation could be caused by the hepatic arterial ischemia in this experimental model. Thus, as has been described in the orthotopic liver transplantation, the heterotopic one might require a double vascularization, both portal and arterial.     

Orthotopic liver transplantation in the rat. Technique using cuff for portal vein anastomosis and biliary drainage.

In orthotopic liver transplantation in the rat, cuff techniques have been developed for anastomoses of the portal vein and bile duct. These techniques have shortened the clamping time of the portal vein and have resulted in fewer biliary complications improving survival of the liver graft. Eighty-three per cent of the grafted animals have survived for 1 week and several animals have survived for more than 6 months. We believe that use of the cuff method technically simplifies microvascular anastomoses. It may be particularly useful for anastomosis of the portal vein after machine preservation of the donor rat liver.     

Liver transplantation in the rat. Technical considerations apropos of 247 cases

A technique is described for orthotopic liver transplantation in the rat using polyethylene cuffs to re-establish subhepatic cava and portal vascular anastomoses. This procedure reduces the time of portal clamping, an important factor of survival. The method was employed in 247 animals during studies to evaluate allograft tolerance and rejection mechanisms in rats of pure strain.     

Orthotopic intestinal transplantation using the cuff method in rats: a histopathological evaluation of the anastomosis.

Segmental small intestine transplantation (SIT) in rats, using a cuff technique, has achieved a high success rate. However, there have been few reports on the influence of the foreign body reaction to polyethylene cuff on vessel anastomoses and graft after SIT. This study involves the histopathological examination of the site of cuff anastomosis and grafts in the short- and long-term survival of segmental SIT. The data obtained from the suture anastomosis model also served as a control. One week after heterotopic segmental SIT using the cuff technique, orthotopic continuations were carried out in syngeneic combination. Twenty-five of 30 rats surviving >200 days (83.3%) were examined for vessel anastomosis. All arterial anastomoses were patent, but the portovenous anastomoses in 10 grafts (33%) were totally occluded and were associated with the formation of collateral vessels. Histopathological examination demonstrated good patency of the artery and vein anastomotic site in the short term, but granulation, fibrosis, and neovascularization at the anastomosis site surrounding the cuffs in the long-surviving group. However, the grafts appeared to be intact, with normal features of the villi. On the contrary, the site of the sutured anastomosis in the long-survival rats showed no inflammatory reaction. Although a polyethylene cuff caused foreign body reaction, the graft blood supplies were maintained by collateral vessels. Considering the low mortality and high success rate, polyethylene cuff is good for short-term study and an alternative method for long-term SIT experiments.     

An improved model for rat liver transplantation including arterial reconstruction and simplified microvascular suture techniques.

For experimental liver transplantation in the rat, the models that have been used most frequently do not include reconstruction of the arterial blood supply to the liver. In these procedures, specially developed cuff anastomoses rather than the conventional microvascular suture technique are used almost exclusively in the recipient operation, so that the anhepatic time is minimized. In this study the technical details of an improved rat model for orthotopic liver transplantation are described. During the donor operation in this experimental method, the liver is prepared with an arterial pedicle that includes the abdominal segment of the aorta, permitting perfusion in situ of the portal vein as well as the hepatic artery. The transplantation of the excised donor organ into the recipient site is carried out with simplified microvascular suture techniques and includes reconstruction of the arterial supply to the liver. Anastomosis of the bile duct is accomplished by choledocho-choledochostomy with a splint technique and supplemental suturing. For the entire procedure, magnifying glasses with 2- to 2.5-fold magnification are sufficient. When this technique has been mastered, the average duration of the anhepatic phase is about 20 min, well below the critical 30-min limit for survival of the experimental animals. As proficiency increased, the perioperative mortality was reduced to 9.2% (n = 130). With the combination of portal and arterial in situ flushing during the donor operation and the rearterialization of the transplant during the recipient operation, the clinical conditions can be approximated more closely than is possible when the transplanted rat liver is supplied only by the portal vein. Use of microvascular suture techniques, without cuff anastomoses, reduces the need for ex situ handling of the donor organ.     

Rescue of Acute Portal Vein Thrombosis After Liver Transplantation Using a Cavoportal Shunt at Re-transplantation

BACKGROUND: Portal vein thrombosis is a rare but devastating complication following orthotopic liver transplantation. Fulminant liver failure ensues with acute portal vein thrombosis after transplantation limiting the treatment options. METHODS: We successfully re-transplanted a 46-year-old female patient who developed acute portal vein thrombosis 19 d after orthotopic liver transplantation. Vascular reconstruction included a cavoportal shunt to augment portal blood flow. RESULTS: Twelve months after re-transplantation this patient lives independently and enjoys excellent liver allograft function. CONCLUSIONS: Cavoportal shunt can augment portal blood flow in adult recipients of orthotopic liver transplants. This technique can be successfully employed during re-transplantation when portal blood flow is inadequate to maintain patency.     

原位肝移植术后门静脉并发症的诊治

目的 探讨原位肝移植术后门静脉并发症的诊断和治疗.方法 回顾性分析173例原位肝移植患者的临床资料.结果 本组原位肝移植术后有6例门静脉并发症(3.5%),门静脉狭窄发生率为1.2%,门静脉血栓发生率为2.3%,且术前3例有门静脉血栓,3例有门静脉高压症手术史.2例患者成功放置血管内支架,3例患者行套扎术或硬化剂治疗后好转出院,6例中无1例死亡.结论 术前存在门静脉高压症手术治疗史和门静脉血栓是门静脉并发症的高危因素.彩色多普勒超声检查是监测门静脉并发症的有效方法 ,确诊门静脉并发症则要依据门静脉CT血管成像.晚期门静脉血栓溶栓治疗效果不佳,对单纯性门静脉狭窄行介入治疗是安全可行的.     

Orthotopic liver retransplantation in rats

A surgical experience with a method of rat orthotopic liver retransplantation (OLRT), and a preliminary study of immunological responses after OLRT are reported. OLRT was performed on the same recipient after the first orthotopic liver transplantation (1st-OLT) according to our original (Kamada's) cuff method. Replacement of the portal vein (PV) and infra-hepatic vena cava (IHVC) cuffs was not technically difficult. However, there were no survivors from the first 6 retransplanted rats, mainly due to complications from defective supra-hepatic vena cava (SHVC) anastomoses. Unlike the human intra-abdominal SHVC, the posterior wall of the intraabdominal SHVC in rats is too short and fragile to perform an end-to-end anastomosis twice between donor and recipient SHVC. For a second group of seven retransplants, a modification of the SHVC anastomosis was made between donor and recipient SHVC in conjunction with the recipient's cuff diaphragm. This enabled reanastomosis to be secure, resulting in the improved 1-week survival after isogeneic OLRT (85.7%). This OLRT model has been applied to the fully allogeneic combination for several immunological studies and led to novel findings. Thus, an experimental model of a rat orthotopic liver retransplant model has the potential to allow more valuable insights into the immunological study of chronic rejection, sensitization and chimerism following liver retransplantation. © 1995 Wiley-Liss, Inc.     

门脉建立侧袖式大鼠肝/小肠整块联合移植模型

目的 建立大鼠肝、小肠整块联合移植模型.方法 用Wistar大鼠行同种异体肝、小肠整块联合移植.肝肠联合移植整块切取移植物时,保留门静脉完整性,利用供体腹段下腔静脉在门静脉侧壁上建立一侧袖,并安置套管.然后按kamada二套管法行原位肝移植,动脉重建通过供体腹主动脉与受体腹主动脉行端侧吻合以建立肠系膜上动脉及肝固有动脉血供.回肠末端在右下腹造瘘.结果 手术成功率为86%,动物平均存活时间大于30 d.病理组织学检查发现移植肝和小肠结构正常.结论 用门脉建立袖套式血管吻合技术施行大鼠肝、小肠整块联合移植模型是可行的.     

肝移植围手术期门静脉血栓的处理

目的 探讨肝移植围手术期门静脉血栓（PVT）的处理。方法 回顾性分析中国医科大学附属第一医院1995年5月至2008年6月实施的194例肝移植病人临床资料,术前存在PVT 24例,其中Ⅰ级12例,Ⅱ级9例,Ⅲ级2例,Ⅳ级1例。术中采取不同门静脉重建方式,结扎术前存在的门腔分流和粗大的侧支循环。术后根据凝血酶原时间（PT）,应用普通肝素或低分子质量肝素预防性抗凝。术中、术后应用多普勒超声监测门静脉血供。结果 术后PVT发生率2.58%（5/194）。1例PVT经外科门静脉取栓、重新吻合治愈,3例置管溶栓、支架植入治愈,另1例仅表现肝功能轻度异常,未特殊处理。与PVT相关病死率为0。其余病例随访6~ 104个月,未见PVT。结论 理想的门静脉重建方式、结扎门腔存在的分流和术后有效的抗凝可以减少PVT的发生,多普勒超声监测能早期发现PVT,挽救移植物,避免再移植。     

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??Management of portal vein thrombosis during the perioperative period of orthotopic liver transplantation WU Gang, LIU Yong-feng,CHENG Dong-hua??et al. Department of General Surgery, the First Affiliated Hospital,China Medical University,Shenyang 110001,China Corresponding auther: LIU Yong-feng, E-mial: yfliu@mail.cmu. edu.cn Abstract Objective To analyze the managements of portal vein thrombosis(PVT) during the perioperative period of orthotopic liver transplantation.Methods Between May 1995 to June 2008,194 orthotopic liver transplantation were performed in our institute,of which 24 presented portal vein thrombosis .12 were grade ??,9 grade ??,2 grade ?? and 1 grade ?? . The management of PVT depended mainly on its extent.Ligation of the collateral circulation,especially spontaneous or surgical splenorenal shunt,was made as approaches to improve portal flow. Heparin or low-molecule-weight heparin as a prophylactic anticoagulation therapy was maintained during and after operation if prothrombin time is less than eighteensonds. Follow-up Doppler ultrasonography was used daily in the early postoperative period.Results After a follow-up of 6-104 months, overall incidence of portal vein thrombosis was 2.58%(5/194).Surgical thrombectomy and revascularization was carried out in 1 case. Percutanous thrombolysis ,balloon angioplasty, or stent placement via portal vein were performed in 3 cases.No treatment was given in 1 patient without hepatic dysfunction. Mortality related to portal vein thrombosis was 0.Conclusion PVT might be avoid by performing a ideal technique for managing PVT as often as possible,by ligation of portosystemic shunt during surgery, and by postoperative anticoagulation.Close follow-up by Doppler ultrasonography may make a prompt diagnosis and reduce PVT-derived loss of grafts.     

用袖套式血管吻合法建立大鼠肝、肠联合移植模型

目的 建立肝、肠联合移植手术模型。方法 用Ｗｉｓｔａｒ大鼠行同种异体肝、肠联合移植。先行肝移植,再行小肠移植。肝脏为原位移植,供肠异位移植于左肾处（切除左肾）。门静脉、肝下下腔静脉和肠系膜上静脉采用袖套式吻合法分别与受者的门静脉、肝下下腔静脉和左肾静脉吻合,回肠末端在左下腹造瘘。结果 手术成功率为６２．５％,动物平均存活时间１１．２ｄ。组织学检查发现移植肝和小肠发生排斥反应。结论 用袖套式血管吻合     

Technic for orthotopic hepatic transplantation in rats using cuffs for 3 vascular anastomoses

A technique for orthotopic hepatic transplantation in the rat uses polyethylene cuffs to re-establish vascular and biliary continuity. Introduction of the suprahepatic cuff into the intrahepatic vena cava of the receiver rat, after partial hepatectomy, reduces the duration of vascular clamping and improves survival of grafted rats (long-term survival: 70%). This technique is simple to reproduce after several weeks of training and can allow research teams to study immunologic mechanisms of tolerance or rejection of liver allografts in the pure strain rat.     

原位肝移植后门脉高压和脾功能亢进的恢复过程

采用全血细胞计数监测和彩色多普勒超声断层的方法对两例因肝硬化合并门脉高压脾功能亢进而行同种异体原位肝移植术的患者进行了临床观察。全血细胞计数监测显示；与术前相比，红细胞计数在术后一个月之内未见明显改善，一个月之后逐渐恢复近于正常。术后１３天白细胞计数和血小板计数恢复至正常范围。     

Effect of rearterialization on short-term graft function in orthotopic rat liver transplantation.

The orthotopic liver transplant model in rats has been very useful for immunological studies. However, differing opinions exist as to whether rearterialization of the graft is necessary for such experiments. Therefore, in this study we evaluated the short-term allograft function when rearterialized was compared to restored venous portal flow only and in situ hepatic artery ligation. The technique of orthotopic liver transplantation in the rat with and without rearterialization of the graft is described in detail. In addition, we evaluated the technical feasibility of sutured vascular anastomosis as compared to the traditional cuff technique. Urea synthesis rate was used as a sensitive marker of integrated liver function, including uptake, synthesis and excretion. Standard liver test of bilirubin, plasma aspergine aminotransferase and alanine aminotransferase were measured. We found no significant differences in the biochemical markers between allografts with portal venous flow only compared to the combination with arterial flow. Autopsy was performed after the biochemical studies at day 14. Histopathological analyses revealed no differences between the two groups of transplanted rats. The patency of sutured anastomoses was in our hands found to be superior to that of the cuff technique, with a success rate of more than 90% in rats with portal venous flow. This rat model in which vascular anastomosis is performed with a running suture technique and without rearterialization seems to be excellent for short-term studies of preservation and liver function after orthotopic liver transplantation.     

大鼠部分肝移植的实验研究

目的 建立稳定的大鼠部分肝移植动物模型,以对移植肝的功能、移植肝的增殖活性进行研究。方法 采用雄性SD大鼠,用两袖套法行活体供肝移植,设部分肝移植组、全肝移植组及部分肝切除组。分别于术后不同时间段取血检测总胆红素、丙氨酸转氨酶、天冬氨酸转氨酶及谷氨酰转移酶;取肝组织行组织学检查。结果 部分肝移植组和全肝移植组术后受者存活时间的差异无显著性;各组术后1周肝功能酶学指标增高,后逐步降至正常;组织学检查可见大量单核细胞浸润,特别是在门静脉周围汇管区,术后1个月细胞浸润和坏死减少,可见胆管增殖;肝切除和部分肝移植组的肝组织可见线粒体肥大以及二倍体和多倍体的肝细胞,中央小静脉、肝窦和叶间静脉轻度扩张;术后300d,各组的肝组织结构基本正常。结论 本模型是研究活体供肝部分肝移植的较好模型。     

Portal blood flow and liver regeneration in auxiliary partial orthotopic liver transplantation in a canine model

Functional competition has been shown to lead to a detrimental outcome in auxiliary liver transplantation. We evaluated the interaction in auxiliary partial orthotopic liver transplantation between the native liver and the graft in terms of portal flow and regeneration. The need for diversion of the portal flow to the graft was also assessed. Reduced-size liver grafts were transplanted orthotopically after partial hepatectomy in beagles. There were two groups: the preserved group, where portal inflow to the native liver was preserved, and the ligated group, where it was interrupted. Portal flow was measured serially and liver regeneration was evaluated on postoperative day 5. Functional competition was not observed in the preserved group. On the other hand, ligation of the native liver portal vein had no obviously detrimental effects on the remnant native liver. This leads to the conclusion that the portal vein to the native liver can be safely ligated to prevent functional competition.     

Left renal vein ligation for large splenorenal shunt during liver transplantation

Adequate hepatopetal portal vein blood flow is obligatory to ensure proper liver function after liver transplantation. Large collateral veins as shunts impair portal vein flow and even cause hepatofugal blood flow and portal steal syndrome. In particular, splenorenal shunts in liver transplant recipients can lead to allograft dysfunction and possible allograft loss or hepatic encephalopathy. Restoration of portal flow through left renal vein ligation (LRVL) is a treatment option, which is much easier compared to splenectomy, renoportal anastomosis and shunt closure, but bears the risk of moderate and temporary impairment of renal function. In addition, a patent portal vein is mandatory for LRVL. However, although LRVL has been reported to be an effective, safe and easy method to control portacaval shunts and increase hepatopetal flow in some studies, indications and safety are still not clear. In this review, we summarize existing studies on LRVL during liver transplantation.     

Refined techniques for intestinal transplantation in rat

Intestinal transplantation (IT), unlike other solid-organ transplantations, such as liver, kidney, and heart, has relatively disappointing results in humans. Significant advances have been made during the past 40 years, but rejection, graft-versus-host disease (GVHD), and infection remain the major obstacles to successful IT. These aspects may be studied using a rat model of IT. Without a microscope and traditional suture for vascular reconstruction, we simplified the procedure using a "three cuffs" technique for orthotopic intestinal transplantation (OIT). Technical modifications of our OIT model that induced good results included (1) adopting a "double cuffs" technique on the graft aorta, (2) using a portal cuff anastomosis to reconstitute the natural and physiologic portal graft drainage with the cuff fixed to the recipient first, and (3) administering a large volume of crystalloid or whole blood to maintain blood pressure and reduce ischemic injury to the graft during operation. In our group, the survival rate of recipients was 87.5% (21 of 24 rats), the average volume of bleeding in the recipient operation was less than 1 mL, and the cold ischemic time, 50 +/- 11 minutes.