Sutureless anastomoses using magnetic rings in canine liver transplantation model

Background

In the first posttransplant month, the most frequent complications are due to technical problems related to complex vascular and bile duct reconstructions during the operation. Moreover, despite great improvements in suturing technique and materials, severe organ ischemia-reperfusion caused by time-consuming hand suturing is still an important factor in graft survival. During the operation, severe hypotension, hypoxic acidosis, hyperkalemia, and renal dysfunction may occur during the anhepatic phase due to the prolonged venous clamping time required for hand suturing. Therefore, hand suturing is a handicap in the development of further advancements in liver transplantation. In this study, we aimed to test a new “mechanical installation method” for rapid vascular reconstruction.

Methods

The magnetic pinning-ring device was developed consisting of paired magnetic rings coated with titanium oxide and embedded in a polypropylene shell. The rings were equipped with alternately spaced holes and titanium pins. Forty adult mongrel dogs were randomly divided into groups: A (n = 16), all vascular and bile duct reconstruction by magnetic ring without venous bypass; B (n = 16), all vascular and bile duct reconstruction by hand suturing with venous bypass; C (n = 8), sham transplantation group, transection of all vessels and common bile duct followed by anastomosis with the magnetic rings without liver transplantation. From groups A and B, dogs were randomly selected as donors (n = 8) or recipients (n = 8) of liver transplantations. We recorded operation time, vascular and bile duct anastomosis time, anhepatic time, administration of supplemental fluids during operation, and survival; blood samples were collected for the detection of liver damage (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]) and tumor necrosis factor α level. Patency was confirmed using ultrasound scans at various time points as late as 24 wk after surgery. Angiography was used to evaluate the anastomoses formed with magnetic rings. In group C, gross observation, histologic staining, and scanning electron microscopy were used to evaluate the vessels and bile ducts 12 wk postoperatively.

Results

In group A, the total operation time, inferior vena cava, and portal vein anastomosis times were significantly shortened, and the anhepatic phase was reduced to about one-fifth that of group B, which was a significant difference between the two groups (P < 0.01). The mean total operative time was 2.54 ± 0.45 h. In order to maintain adequate blood pressure, the mean fluid volume infused was 800.56 ± 60.56 mL in the recipients of group A, which was lower than that in group B (2241.67 ± 390.78 mL, P < 0.01). Use of a pressor agent in group A was unnecessary. After operation, five of eight animals in group A survived more than 7 d after operation. The main cause of death was acute rejection. Only three of eight animals in group B survived more than 1 wk after operation due to chronic anastomotic bleeding, kidney failure, heart failure, and gastrointestinal bleeding. There was a statistically significant difference (P < 0.01) between the short-term survival rate in the two groups (75.0% versus 37.5%). The ALT (1544.46 ± 286.27) U/L and AST (1710.74 ± 252.27) U/L levels after operation in the animals with hand suturing were significantly higher than those in the sutureless group (ALT = 1116.41 ± 210.55 U/L; AST = 1176.95 ± 248.25) U/L after reperfusion (P < 0.01). The serum tumor necrosis factor α levels (45.56 ± 10.78) ng/L in group B were significantly higher than those of group A (26.64 ± 10.84) ng/L after reperfusion (P < 0.01). Re-endothelialization was confirmed in all vessels in group C, with neither formation of aneurysms nor thickening of the vascular wall noted after 12 wk. The bile duct anastomoses also healed well.

Conclusions

The magnetic pinning-ring device offers a simple, fast, reliable, and efficacious technique for nonsuturing vascular and bile duct anastomoses. Use of this device shortens operation time, maintains a high patency rate, and improves the healing of tissue. Application of the magnetic ring anastomosis technique can effectively reduce the complications caused by hand suturing, and can reduce the extent of ischemia-reperfusion injury, leading to smoother operations and improved prognosis.     

A novel paper cuff for vascular reconstruction in canine liver transplantation

A new, simple method of producing optimal cuffs using thin paper and then setting it in resin for vascular reconstruction in canine liver transplantation is herein described. Thin Paper was cut into a paper tape strip. By fixing both ends of this paper tape, a cylinder paper core of any desired size could thus be obtained. The paper core was immersed into a two-liquid mixture-type resin, removed, and left to harden. The paper cuffs (0.2mm or less in thickness) were then used for anastomoses of the portal vein and the infrahepatic inferior vena cava in a series of 10 consecutive canine liver transplantations. Out of 10 animals, 8 survived for more than 5 days. The vascular patency in these 8 animals at the cuff anastomotic sites was 100% at postmortem. We therefore conclude that this paper cuff appears to be useful for various types of experimental liver transplantations in large animals.     

肝移植中血管异常时的血管重建

目的:探讨肝移植过程中血管异常时血管重建的方式和方法.方法:对16例肝移植的供肝动脉变异、受体肝动脉异常和受体门静脉血栓形成采用了多种方法进行重建,术后采用彩色多普勒超声检查的方法监测重建血管的通畅情况.结果:肝移植术后,14例重建的血管通畅良好,生存正常;1例术后7d发生门静脉血栓形成,并于术后4周死于消化道大出血;1例术后7d死于药物引起的严重的血管内溶血,但重建血管通畅良好.结论:根据各种血管异常时血管重建的原则和选择适当的血管重建方式是保证肝移植成功的关键.     

Outcome of extra-anatomic vascular reconstruction in orthotopic liver transplantation

BACKGROUND: Portal venous and hepatic arterial reconstruction are critical to successful outcomes in orthotopic liver transplantation (OLT). With portal vein thrombosis or inadequate hepatic arterial inflow, extra-anatomic vascular reconstruction is required. However, the clinical outcomes following extra-anatomic vascular reconstruction are largely unknown. METHODS: To determine the outcomes associated with extra-anatomic vascular reconstruction, we performed a retrospective review of 205 OLT recipients transplanted between 1995 and 2000. RESULTS: Extra-anatomic portal venous inflow was based upon the recipient superior mesenteric vein using donor iliac vein graft in a retrogastric position (n = 12). Extra-anatomic arterial inflow was based on recipient infrarenal aorta using donor iliac artery graft through the transverse mesocolon (n = 25). OLT with routine anatomic vascular construction served as control (n = 168). Extra-anatomic vascular reconstruction was not associated with increased morbidity, mortality, operating room time, length of stay, or thrombosis. CONCLUSION: We conclude that extra-anatomic vascular conduits are associated with excellent long-term outcomes and provide acceptable alternatives for vascular reconstruction in OLT.     

Novel technique for blood circuit reconstruction in mouse heart transplantation model

PURPOSE: The surgical technique of heterotopic abdominal heart transplantation in mice, a standard model for transplantation immunology research, is very challenging restricting the widespread use of this model. A novel technique for the blood circuit reconstruction in heterotopic abdominal heart transplantation was developed. METHOD: The new method makes use of the suprahepatic inferior vena cava instead of the pulmonary artery of the donor heart for the anastomosis to the infrarenal vena cava of the recipient. FINDINGS: The sutures for the double vessel anastomoses were completed within 20.8+/-1.3 min, which was significantly shorter than 27.5+/-1.3 min in the traditional method. Similarly, the heart rebeating time postoperation (1.1+/-0.2 min) was significantly shortened as compared to 2.1+/-0.4 min using the traditional method. CONCLUSION: This novel technique facilitated abdominal heart transplantation in mice with reduced warm ischemia and grafted heart rebeating time.     

小鼠异位心脏移植血液循环重建模型的建立

目的 建立新的一种简单、稳定的小鼠腹腔异位心脏移植模型.方法 将供体心脏肝上下腔静脉与受体下腔静脉端侧吻合,供体升主动脉与受体腹主动脉端侧吻合.用C57BL/6J (H-2b)作供体和受体做同基因心脏移植,用C57BL/6J (H-2b)作供体BALB/C (H-2d)受体做同种异体心脏移植.结果 新方法血管吻合时间(21.3±1.6)min比传统方法吻合时间(28.5±1.4)min明显缩短,心脏复跳时间从(2.3±0.9)min降低到(1.4±0.5)min.同基因和同种异体移植的两种方法比较,1周生存率差异无统计学意义(P>0.05).结论 小鼠心脏移植新模型明显缩短移植物温缺血时间,有利于移植物长期存活.     

Novel technique for suprahepatic vena cava reconstruction in rat orthotopic liver transplantation

In previous studies, the suture technique and the cuff method were applied to anastomoses of the suprahepatic vena cava (SHVC) in rat orthotopic liver transplantation. However, the anastomosis of SHVC is difficult during transplantation because of the short length of the SHVC. Here, we developed a novel method for anastomoses of SHVC, using a veno-lined stent technique. The veno-lined stent for SHVC anastomosis was prepared after the donor operation. The special veno-lined stent was a 4.0-mm-long polythene tube in which a venous segment from the donor was lined. During the recipient operation, the donor SHVC was anastomosed end-to-end to the recipient SHVC, using the veno-lined stent. Anastomoses of the portal vein and infrahepatic vena cava were performed using a cuff technique. Continuity of the bile duct was established using a stent. The hepatic artery was ligated, and the graft was not arterialized. As controls, the unlined stent, the suture technique, and the cuff method were also used for SHVC anastomoses, respectively, as three control groups with the identical procedures above. In total, 30 orthotopic liver isografts were performed using the veno-lined stent technique. The survival rate was 90% (27/30) after 1 week and 70% (21/30) after 2 months, with normal hepatocellular function. The SHVC anastomosis using a veno-lined stent took 10 +/- 2 (mean +/- SD) min. The anhepatic phase, recipient operative time, and complete operation time were about 14 +/- 2 min, 40 +/- 5 min, and 120 +/- 10 min, respectively. However, in the nonlined stent control group, a total of 20 orthotopic liver isografts used the nonlined stent for SHVC anastomoses, and all failed because of venous thrombosis in SHVC; none survived over 1 week. In the suture technique control group, 40 orthotopic liver isografts were performed using a suture technique for SHVC anastomoses. The results showed no significant difference with those of the veno-lined stent method. But in the cuff method control group, of all 20 orthotopic liver isografts performed using the cuff method for SHVC anastomoses, 10 failed because of failed ligation on the anastomostic site. The survival rates at 1 week and 2 months postoperatively were significantly different from those of the veno-lined stent method. The veno-lined stent technique provides a novel, simple, and reliable method for SHVC anastomoses. It avoids bleeding during suture and the ligation difficulties found with the cuff method. The operation's success rate is satisfactory. This model is successful, and could be applied in various experimental studies.     

改良犬原位背驮式肝移植的解剖学观察

目的观察犬肝脏解剖学特点,探索建立改良的犬同种异体原位背驮式肝移植模型。方法对15只杂交犬的肝脏进行活体和尸体标本的解剖观察。结果犬肝共分7叶,门静脉分左右支进入肝脏,门静脉左支供应约70%肝组织(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ叶),门静脉右支供应约30%肝组织(Ⅵ、Ⅶ叶),分别阻断门静脉左、右支后5 min左右门静脉压力达到峰值,并迅速回复至门静脉正常压力值上限范围内;肝动脉和胆管与门静脉分支伴行进入各肝叶;左肝静脉粗大,可以作为肝静脉重建的流出道,其余3~6支肝静脉可以分别结扎,肝后下腔静脉易于与肝脏分离。结论犬肝的解剖学特点适宜于建立改良的原位背驮式肝移植模型。     

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.     

Complex vascular reconstruction using donor's vessel grafts in orthotopic liver transplantation

The vascular abnormalities of recipients are associated with reconstructive difficulties with an increased risk of postoperative complications. We performed an orthotopic liver transplantation that required a complex vascular reconstruction using donor vascular grafts. A patient with hepatitis B virus cirrhosis received a liver from a brain-dead donor. Dynamic computed tomography revealed complete obstruction of the portal vein due to thrombosis as well as narrowing of the hepatic arteries. We employed orthotopic liver transplantation using the piggy-back technique with complex reconstruction of the portal vein and the hepatic arteries. For portal vein reconstruction, we used the donor's iliac vein as an interpositional conduit from the recipient's gastric coronary vein to graft the portal vein. The hepatic arteries of the graft were reconstructed at the back-table before anastomosis to the side of superior mesenteric artery using an interpositional conduit of the donor's external iliac artery. All postoperative studies revealed good graft function with an excellent blood flow through all vascular anastomoses during the first year postoperatively.     

Problematic vascular reconstruction in liver transplantation. Part I. Arterial

Arterial inflow is essential for graft function after liver transplantation. Sometimes the recipient celiac axis is not suitable for anastomosis, and in these cases a conduit from either the aorta or iliac artery is an alternative. We retrospectively reviewed 32 patients who required arterial conduits and compared them with a matched control group who underwent standard arterial reconstruction (donor celiac artery to recipient celiac artery). The indications and surgical technique for arterial conduits are presented. There were no differences in intraoperative vascular flow studies, postoperative liver function, or incidence of rejection in the two groups. There were, however, more deaths in the conduit group, two of which are related to the retropancreatic conduit technique, with the others caused by the patients' underlying condition at transplantation. There was no morbidity or death associated with the antepancreatic conduit techniques. We therefore believe the use of arterial conduits from the aorta or iliac artery, when placed antepancreatically, are safe and should be used without reservation when indicated.     

Biliary-type cytokeratin pattern in a canine isolated perfused liver transplantation model

BACKGROUND: Ischemia-reperfusion (I/R) injury in liver transplantation units and the influence of I/R injury on bile flow dynamics is being intensely investigated in various animal models, but the expression of intracellular intermediate filaments of biliary type as an early sign of cholestasis has not been yet explored. METHODS: We studied the hepatic elimination kinetics of indocyanine green (ICG), an exclusively biliary excreted cholephilic dye, and the functional and morphological integrity of liver cells in a canine liver transplantation model following I/R. During reperfusion following cold ischemia, we evaluated the ICG excretion curves, biochemical signs of liver damage, the bile canaliculus of the hepatocytes by electron microscopy, and the expression of intermediate filaments of cytokeratin type by immunohistochemistry. RESULTS: Impairment of the biliary ICG excretion was directly related to ischemia time, but hepatocellular ICG uptake and bile flow rate were not significantly reduced. Liver enzymes increased as early as 6 h of ischemia and hepatocytes showed an increase of the bile canaliculus area. This was correlated to a membranous to cytoplasmatic staining of the cytoskeleton of the hepatocytes. CONCLUSIONS: To the best of our knowledge, this is the first evidence of cholestatic changes starting early following cold ischemia in a canine isolated perfused liver transplantation model despite prompt recovery of the bile flow.     

Problematic vascular reconstruction in liver transplantation. Part II. Portovenous conduits

Eight of 265 orthotopic liver transplant procedures performed at this institution since December 1984 have used venous conduits to reconstruct an occluded portal system and supply portal blood to the allograft. The factors mandating the use of these conduits were variable, and several reconstructive techniques were used. We present a series of patients with various conditions in which portal conduits were indicated and describe and illustrate the inherent technical considerations.     

犬辅助性原位肝左叶移植模型的建立

目的建立稳定可靠的辅助性肝移植动物模型。方法杂交犬14条8～25kg随机分两组。供体组肝脏均采用尸体肝左叶；受体组行标准左叶切除，供肝左叶原位移植于受体体内。结果供肝热缺血时间为零，冷缺血时间平均36．3min；灌注液的量平均2．96L，切取修剪肝左叶时间为23～40min。受体手术平均时间5．3h，平均出血量140ml，肝脏血管重建后红润柔软，5～11min内即见胆汁从胆管中溢出。受体组术后全部存活，围手术期未用任何血管活性药物、抗生素及免疫抑制剂。术后存活超过6h者5例．最长存活者达5．7d。结论犬是建立辅助性肝移植模型的理想动物。     

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.     

Biliary tract reconstruction in liver transplantation

Biliary tract complications are often referred to as the Achilles' heel of liver transplantation and various techniques have been developed to overcome them. The two major methods of bile duct reconstruction currently in use consist of either (1) choledochocholedochostomy over a T-tube or, when duct-to-duct approximation is not feasible, choledochojejunostomy over an internal stent, or (2) interposition of the donor gallbladder as a conduit between the donor bile duct and either the recipient bile duct or a jejunal loop. Although these standardizations of biliary tract reconstruction have resulted in a reduction of biliary complications after liver transplantation, further advancement in the elucidation of ampullary obstruction and viability of the donor bile duct is needed.     

Bile duct reconstruction in liver transplantation

Complications of the biliary anatomosis are common after liver transplantation. Even with improved techniques the frequency of biliary complications is approximately ten percent. Main reason for this high morbidity rate is the unfavourable blood supply to the biliary tract. A variant of reconstructions has been described and recommended. The end-to-end-choledochocholedochostomy over a T tube turned out to be the preferred technique in most centers. In cases of different diameter of donor and recipient biliary tract, the side-to-side-choledochocholedochostomy provides a relayable alternative method. When the length of the bile duct doesn't allow direct anastomosis, the gallbladder-conduit may help to overcome this problem. The choledochojejunostomy with Roux-en-Y loop has become a frequently used biliary anastomosis, especially when the recipients bile duct is absent or otherwise destroyed. - Our own experience with fourteen liver transplantations shows biliary tract complications in three cases: a leakage and a stenosis of the anastomosis after choledochocholedochostomy were successfully transformed to a hepaticojejunostomy. In the third case, intrahepatic biliary stenosis were treated by percutaneous transhepatic dilatation.