Infrahepatic Caval Vein Research Articles

A new rat model of auxiliary partial heterotopic liver transplantation with liver dual arterial blood supply.

Auxiliary partial heterotopic liver transplantation (APHLT) with portal vein arterialization is a valuable procedure to be considered in the treatment of patients with acute liver failure and metabolic liver diseases. The aim of this study was to develop a new rat model of APHLT with liver dual arterial blood supply (LDABS). A total of 20 rats were used. The donor liver was resected, and the celiac trunk was reserved. Left and medial hepatic lobes accounting for 70% of the liver mass were removed en bloc and the suprahepatic caval vein was ligated simultaneously. Thus, 30% of the donor liver was obtained as the graft. Sleeve anastomosis of the graft portal vein and splenic artery were performed after narrowing the portal vein lumen through suturing. The right kidney of the recipient was removed, and sleeve anastomosis was performed between the celiac trunk of the graft and the right renal artery of the recipient. In addition, end-to-end anastomosis was performed between the infrahepatic caval vein of the graft and the right renal vein of the recipient. Following the reperfusion of the graft, the blood flow of the arterialized portal vein was controlled within the physiological range through suturing and narrowing under monitoring with an ultrasonic flowmeter. The bile duct of the graft was implanted into the duodenum of the recipient through an internal stent catheter. A 70% section of the native liver (left and medial hepatic lobes) was resected using bloodless hepatectomy. The mean operative duration was 154.5±16.4 min, and the warm and cold ischemia times of the graft were 8.1±1.1 min and 64.5±6.6 min, respectively. The blood flow of the arterialized portal vein to the graft was 1.8±0.3 ml/min/g liver weight. The success rate of model establishment (waking with post-surgical survival of >24 h) was 70% (7/10). Following successful model establishment, all rats survived 7 days post-surgery (100%; 7/7). The graft was found to be soft in texture and bright red in color following exploratory laparotomy. In conclusion, a new rat model of APHLT with LDABS without stent for vascular reconstruction was developed. This is a feasible and reliable rat model for liver transplantation study.

Radical Nephrectomy in a Horseshoe Kidney with Endo-Caval Thrombosis: Infrahepatic Caval Vein Control with Piggy-Back Technique

Introduction: Renal cell carcinoma with vascular invasion of vena cava is still a great challenge for uro-oncologists. The surgical approach to this clinical scenario is even more challenging when coupled with anatomical anomalies, like horseshoe kidney and the presence of abnormal vessels. Materials and Methods: In this video, we will show a case of a large left renal tumor in a horseshoe kidney with double renal vein and endo-caval thrombus that reaches the suprahepatic veins (T2b—third level). The video describes, step by step, the piggy-back surgical technique, which allows to completely expose the inferior infrahepatic vena cava, splitting it from the liver that remains connected just to the three suprahepatic veins. This technique, borrowed from the liver transplant, allows, without increasing the risk of intraoperative complications and maintaining a high oncologic efficacy, to have an excellent vascular control that, in cases like the presented one, may avoid recourse to the use of extracorporeal circulation and allows urological equipe to complete the operation, without the aid of cardiac surgeons. Moreover, the video shows how it is possible, on a horseshoe kidney, the presence of abnormal vessels, whose arterial component has to be preserved to maintain a proper blood flow in the residual renal parenchyma. Results: The postoperative course was uneventful, underlining the reliability of the chosen surgical approach. The patient died after 10 months from cardiopulmonary failure. Conclusions: The video shows how it is possible to surgically approach an advanced left kidney cancer on a horseshoe kidney with abnormal vessels and an associated endo-caval thrombus that reaches the suprahepatic veins, without recurring to extracorporeal circulation. The piggy-back technique allows in this case a better exposure of the infrahepatic vena cava, allowing the procedure to be effectively performed. No competing financial interests exist. Runtime of video: 6 mins 54 secs Video technique employed: The video has been shot by one of the surgeons, using a full HD handy cam. The camera has been covered to be sterile and to be used over the field. Video editing has been made using Adobe Premiere and Adobe photoshop (for overlay graphics). Smithmicro POSER and Autodesk 3D studio MAX have been used for tridimensional patient images. A high-end computer has been used to finally render the video in full HD.

Heterotopic Auxiliary Rat Liver Transplantation With Flow-regulated Portal Vein Arterialization in Acute Hepatic Failure

In acute hepatic failure auxiliary liver transplantation is an interesting alternative approach. The aim is to provide a temporary support until the failing native liver has regenerated.1-3 The APOLT-method, the orthotopic implantation of auxiliary segments- averts most of the technical problems. However this method necessitates extensive resections of both the native liver and the graft.4 In 1998, Erhard developed the heterotopic auxiliary liver transplantation (HALT) utilizing portal vein arterialization (PVA) (Figure 1). This technique showed promising initial clinical results.5-6 We developed a HALT-technique with flow-regulated PVA in the rat to examine the influence of flow-regulated PVA on graft morphology and function (Figure 2). A liver graft reduced to 30 % of its original size, was heterotopically implanted in the right renal region of the recipient after explantation of the right kidney. The infra-hepatic caval vein of the graft was anastomosed with the infrahepatic caval vein of the recipient. The arterialization of the donor’s portal vein was carried out via the recipient’s right renal artery with the stent technique. The blood-flow regulation of the arterialized portal vein was achieved with the use of a stent with an internal diameter of 0.3 mm. The celiac trunk of the graft was end-to-side anastomosed with the recipient’s aorta and the bile duct was implanted into the duodenum. A subtotal resection of the native liver was performed to induce acute hepatic failure. 7 In this manner 112 transplantations were performed. The perioperative survival rate was 90% and the 6-week survival rate was 80%. Six weeks after operation, the native liver regenerated, showing an increase in weight from 2.3±0.8 g to 9.8±1 g. At this time, the graft’s weight decreased from 3.3±0.8 g to 2.3±0.8 g. We were able to obtain promising long-term results in terms of graft morphology and function. HALT with flow-regulated PVA reliably bridges acute hepatic failure until the native liver regenerates.

Heterotopic auxiliary rat liver transplantation with flow-regulated portal vein arterialization in acute hepatic failure.

In acute hepatic failure auxiliary liver transplantation is an interesting alternative approach. The aim is to provide a temporary support until the failing native liver has regenerated.(1-3) The APOLT-method, the orthotopic implantation of auxiliary segments- averts most of the technical problems. However this method necessitates extensive resections of both the native liver and the graft.(4) In 1998, Erhard developed the heterotopic auxiliary liver transplantation (HALT) utilizing portal vein arterialization (PVA) (Figure 1). This technique showed promising initial clinical results.(5-6) We developed a HALT-technique with flow-regulated PVA in the rat to examine the influence of flow-regulated PVA on graft morphology and function (Figure 2). A liver graft reduced to 30 % of its original size, was heterotopically implanted in the right renal region of the recipient after explantation of the right kidney. The infra-hepatic caval vein of the graft was anastomosed with the infrahepatic caval vein of the recipient. The arterialization of the donor's portal vein was carried out via the recipient's right renal artery with the stent technique. The blood-flow regulation of the arterialized portal vein was achieved with the use of a stent with an internal diameter of 0.3 mm. The celiac trunk of the graft was end-to-side anastomosed with the recipient's aorta and the bile duct was implanted into the duodenum. A subtotal resection of the native liver was performed to induce acute hepatic failure. (7) In this manner 112 transplantations were performed. The perioperative survival rate was 90% and the 6-week survival rate was 80%. Six weeks after operation, the native liver regenerated, showing an increase in weight from 2.3±0.8 g to 9.8±1 g. At this time, the graft's weight decreased from 3.3±0.8 g to 2.3±0.8 g. We were able to obtain promising long-term results in terms of graft morphology and function. HALT with flow-regulated PVA reliably bridges acute hepatic failure until the native liver regenerates.

V73 Radical nephrectomy in a horseshoe kidney with endo caval trombosis: Infra hepatic caval vein control with Piggy back technique

Introduction: Renal cell carcinoma with vascular invasion of vena cava is still a great challenge for uro-oncologists. The surgical approach to this clinical scenario is even more challenging when coupled with anatomical anomalies, like horseshoe kidney and the presence of abnormal vessels. Materials and Methods: In this video, we will show a case of a large left renal tumor in a horseshoe kidney with double renal vein and endo-caval thrombus that reaches the suprahepatic veins (T2b— third level). The video describes, step by step, the piggy-back surgical technique, which allows to completely expose the inferior infrahepatic vena cava, splitting it from the liver that remains connected just to the three suprahepatic veins. This technique, borrowed from the liver transplant, allows, without increasing the risk of intraoperative complications and maintaining a high oncologic efficacy, to have an excellent vascular control that, in cases like the presented one, may avoid recourse to the use of extracorporeal circulation and allows urological equipe to complete the operation, without the aid of cardiac surgeons. Moreover, the video shows how it is possible, on a horseshoe kidney, the presence of abnormal vessels, whose arterial component has to be preserved to maintain a proper blood flow in the residual renal parenchyma. Results: The postoperative course was uneventful, underlining the reliability of the chosen surgical approach. The patient died after 10 months from cardiopulmonary failure. Conclusions: The video shows how it is possible to surgically approach an advanced left kidney cancer on a horseshoe kidney with abnormal vessels and an associated endo-caval thrombus that VID-2014-0035-ver9-Veneziano_1P.3d 07/26/14 8:32pm Page 1

Energetic recovery in porcine grafts by minimally invasive liver oxygenation

BackgroundGaseous insufflation of oxygen via the venous vascular system has proven to be an effective tool for preventing anoxic tissue injury after extended time periods of ischemic liver preservation. Most experimental studies so far have been undertaken in rat models and include a series of pinpricks into postsinusoidal venules as an outlet for the insufflated gas. Here, we describe a simplified technique for minimally invasive liver oxygenation in porcine grafts, representing a hassle-free access to organ oxygenation without vascular lesions. MethodsWe retrieved livers from Landrace pigs and cold-stored them in histidine-tryptophan-ketoglutarate solution. Subsequent to 18 h preservation, we treated some livers for an additional 2 h with gaseous oxygen, insufflated via silicone tubing inserted into the suprahepatic caval vein. Gas pressure was limited to 18 mm Hg. We occluded the infrahepatic caval vein with a bulldog clamp. Gas bubbles left the graft via the portal vein. We assessed liver integrity by energetic tissue status and by controlled in vitro reperfusion with autologous blood. ResultsMagnetic resonance imaging demonstrated homogeneous gas distribution in the persufflated tissue without major shunting. Biochemical analyses revealed effective and homogeneous restoration of energetic homeostasis in the ischemic graft before reperfusion. Sinusoidal endothelial clearance of hyaluronic acid was significantly improved upon reperfusion, as was hepatic arterial flow. Parenchymal enzyme loss was concordantly mitigated after minimally invasive liver oxygenation. ConclusionsOur results indicate that gaseous oxygen persufflation of the porcine liver is possible without tissue trauma, and significantly enhances post-preservation recovery of the graft.

Liver Transplantation in the Rat: Single-Center Experience With Technique, Long-term Survival, and Functional and Histologic Findings

Orthotopic liver transplantation (OLT) in rats is frequently used as an experimental model. Numerous surgical techniques have been developed that enable the investigator to conduct clinically relevant studies. The objective of this study was to develop a rat model of acute and chronic rejection, to explicitly study technical modifications of vascular anastomoses with precision, and to examine histopathologic and functional changes in the graft. With DA-(RT1av1) rats as donors and Lewis-(RT1) rats as recipients, arterialized OLT was performed using a combined suture, cuff, and splint method. Recipients were divided into 5 groups: syngeneic control rats (group 1), allogeneic control rats (group 2), allogeneic OLT rats with low-dose tacrolimus (FK506) immunosuppression (group 3), allogeneic OLT rats with high-dose tacrolimus immunosuppression (group 4), and allogeneic OLT rats with high-dose tacrolimus immunosuppression and retrograde reperfusion via the infrahepatic caval vein (group 5). After OLT, serum parameters were determined and hepatic biopsy specimens were sampled. We examined the effects of acute rejection with or without immunosuppression therapy at histopathologic evaluation. Liver grafts in syngeneic and allogeneic rats (groups 1, 2, 4, and 5) demonstrated normal serum parameters and histopathologic findings at 10 days after OLT, and 93% survival at 3 months. The simplified technique using 1 suture and 2 cuff anastomoses provided the best short- and long-term survival after OLT in all groups. Retrograde perfusion via the infrahepatic caval vein resulted in lower postoperative liver enzyme values. The present model is feasible, enabling comprehensive preclinical experimental research on liver transplantation. Furthermore, we provide helpful instructions for learning this surgical technique.

Conversion to termino-terminal cavo-cavostomy as a rescue technique for infrahepatic obstruction after piggyback liver transplantation

Conversion to termino-terminal cavo-cavostomy as a rescue technique for infrahepatic obstruction after piggyback liver transplantation

Improved technique of heterotopic auxiliary rat liver transplantation with portal vein arterialization

In acute, potentially reversible hepatic failure, auxiliary liver transplantation is a promising alternative approach. Using the auxiliary partial orthotopic liver transplantation (APOLT) method--the orthotopic implantation of auxiliary segments--most of the technical problems (lack of space for the additional liver mass, the portal vein reconstruction, and the venous outflow) are avoided, but extensive resections of the native liver and the graft are necessary. Erhard described the heterotopic auxiliary liver transplantation (HALT) with portal vein arterialization (PVA). Initial clinical results demonstrated that an adequate liver function can be achieved using this technique. We developed and improved a technique of HALT with flow-regulated PVA in the rat to perform further investigations. The aim of this paper is to explain in detail this improved experimental surgical technique. Liver transplantations were performed in 122 male Lewis rats: After a right nephrectomy, the liver graft, which was reduced to about 30% of the original size, was implanted into the right upper quadrant of the recipient's abdomen. The infrahepatic caval vein was anastomosed end-to-side. The donor's portal vein was completely arterialized to the recipient's right renal artery in stent technique. Using a stent with an internal diameter of 0.3 mm, the flow in the arterialized portal vein was regulated to achieve physiologic parameters. The celiac trunk of the graft was anastomosed to the recipient's aorta, end-to-side. The bile duct was implanted into the duodenum. After improvements of the surgical technique, we achieved a perioperative survival of 90% and a 6-week survival of 80% in the last 112 transplantations. We developed a standardized and improved technique, which can be used for experiments of regeneration and inter-liver competition in auxiliary liver transplantation. Furthermore, this technique is suitable for the investigation of the influence of portal vein arterialization and portal hyperperfusion on liver microcirculation, function, and morphology.

Blood coagulation in anhepatic pigs: effects of treatment with the AMC-bioartificial liver

The function of a newly devised bioartificial liver (AMC-BAL) based on viable, freshly isolated porcine hepatocytes has been evaluated in anhepatic pigs. The aim of this study was to assess the contribution of BAL treatment on blood coagulation parameters. Pigs were anesthetized and a total hepatectomy was performed (n = 15). The infrahepatic caval vein and the portal vein were connected to the subdiaphragmatic caval vein using a three-way prosthesis. Animals received standard intensive care (control, n= 5), treatment with an empty BAL (device control, n= 5) or with a cell-loaded BAL (BAL-treatment, n= 5) for a period of 24 h starting 24 h after hepatectomy. Coagulation parameters studied concerned prothrombin time (PT), platelet count, the procoagulant system (factors (F)II, FV, FVII, FVIII and fibrinogen), anticoagulant system (AT III), fibrinolytic system (t-PA, PAI-1) as well as markers of coagulation factor activation (TAT complexes, prothrombin fragment F1 + 2). FII, FV, FVII, AT III and fibrinogen rapidly decreased after total hepatectomy in pigs in accordance with the anhepatic state of the animals. FVIII levels were not influenced by the hepatectomy. A mild drop in platelet count was seen in all groups. Treatment of anhepatic pigs with the cell-loaded BAL did not restore PT or clotting factor levels. TAT and F1 + 2 complexes, however, were significantly increased in this group. Levels of t-PA and PAI-1 were not influenced by cell-loaded BAL treatment. Treatment of anhepatic pigs with the AMC-BAL based on freshly isolated porcine hepatocytes does not result in an improved coagulation state due to extensive consumption of clotting factors. However, increased levels of TAT complexes and prothrombin fragments F1 + 2 during treatment of anhepatic pigs indicate synthesis and direct activation of coagulation factors, leading to thrombin generation. This demonstrates that this bioartificial liver is capable of synthesizing coagulation factors.

Animal experiment studies of arterialization of the portal vein in liver transplantation using the Göttingen minipig

The aim of the present experimental investigation was to assess the circulatory, biochemical and histopathological consequences of complete portal vein arterialization of the transplanted liver in 'Göttinger' miniature pigs. Orthotopic liver transplantations using a passive portojugular shunt were performed in six male 'Göttinger' miniature pigs. Using an iliac artery segment interposition of the animal donor, the hepatic artery (HA) of the transplant liver was anastomized end-to-end and the portal vein (PA) also united with the internal iliac artery stump end-to-end. The central anastomosis was performed onto the suprarenal aorta. Portal vein blood was drained into the infrahepatic caval vein via an end-to-side shunt (PCS). During the course, the following parameters were determined: arterial blood pressure, venous pressure, cardiac output, electromagnetic blood flow measurements across the HA, PA, and PCS, PA mean pressure, transaminases, partial thromboplastin time and fibrinogen. Liver biopsies and autopsy specimens were investigated. One of six animals died a few hours postoperatively, two of six died after 48 and 72 h, respectively, whereas three pigs survived the scheduled 7 days. The cardiac output fell intraoperatively initially by an average of 20% but had approximately the starting volume of 2.2 l/min at the end of the operation. Although the diameter of the anastomosis was reduced to 4 mm, the flow in the arterialized PA on average was 340 ml/min when the vessel clamp was opened. At the end of operation the mean was 380 ml/min, the interval of measurement being 75 min. The flow across the PCS and the HA were constant during the course. As mechanism for this phenomenon, autoregulation of the liver blood flow on a sinusidal level has been suggested. The biochemical results and the histopathological findings showed no change compared to previous findings in a control group of animals in which liver transplantation was performed by our team. Complete arterialization of the PA is well tolerated in liver transplantation in 'Göttinger' miniature pigs with regard to circulation and liver function in a short-term trial of a maximum of 7 days. Long-term results are still to come.

Involvement of oxygen in harvesting injury of the liver

The present study was undertaken to assess the role of oxygen free radicals relating to cell damage upon reoxygenation of the ischemically altered isolated rat liver. Livers were excised and flushed via the portal vein with Ringer's solution and Euro-Collins solution, to which superoxide dismutase (SOD) was added in the experimental group. After warm ischemia at 37 degrees C and cold storage at 4 degrees C, the livers were reperfused via the portal vein with carbogen-saturated Krebs-Henseleit solution. Other livers were subjected to a retrograde persufflation via the infrahepatic caval vein with either oxygen or nitrogen and then rinsed with Ringer's solution. During reperfusion, SOD-treated livers showed markedly reduced vascular resistance, lower enzyme release and enhanced VO2 accordingly, energy charge at the end of reperfusion was significantly higher in the treated group. With reference to the tissue content of malondialdehyde, SOD-treated livers showed significantly less damage than the corroboration for these data. Enzyme activities in the eluate were significantly reduced under anoxic conditions as well as in the presence of SOD. We conclude from these data that oxygen free radicals do exert a detrimental impact on the reoxygenated liver, which could be specifically suppressed by application of exogenous SOD.