Development of a Simple and Active Shunt System in the Anhepatic Stage for Surgical Training of Orthotopic Liver Transplantation.

BACKGROUND: A pig model has been commonly used for technical training for clinical liver transplantation (LT). However, as the healthy pigs have no shunt bypassing the portal vein (PV), it is necessary to complete LT within 30 minutes after shutting off the PV flow. While a model that uses an ex vivo shunt system has been used to alleviate the constraints of the anhepatic phase, it has been often difficult to keep sufficient blood flow rate and prevent the intestinal congestion because the blood vessels were occluded easily with the suction pressure by using the conventional shunt system. METHODS: We designed a portable shunt system and a novel connector that can prevent the blood vessel from occluding. The system can separately control the flow rate of PV and inferior vena cava (IVC) and detect whether the blood vessels were occluded. By reducing the solution volume in the circuit, the effected blood loss ex vivo could be minimized. The stability of this system was verified with 15 medical doctors in an advanced medical professional education course. RESULTS: The system enabled the blood flow to maintain ≥ 20 mL/minute and prevented the intestinal congestion. The perioperative hemodynamics of the recipient were stable without a blood transfusion using 25 to 40 kg pigs. We confirmed that all LT training were completed, even 60 minutes after shutting off the PV flow. CONCLUSIONS: Our system greatly contributed to training on LT for conducting the survival experiments.

Magnetic Anastomosis Rings to Create Portacaval Shunt in a Canine Model of Portal Hypertension.

PURPOSE: This study evaluated a novel magnetic compression technique (magnamosis) for creating a portacaval shunt in a canine model of portal hypertension, relative to traditional manual suture. METHODS: Portal hypertension was induced in 18 dogs by partial ligation of the portal vein (baseline). Six weeks later, extrahepatic portacaval shunt implantation was performed with either magnetic anastomosis rings, or traditional manual suture (n = 9, each). The two groups were compared for operative time, portal vein pressure, and serum biochemical indices. Twenty-four weeks post-implantation, the established anastomoses were evaluated by color Doppler imaging, venography, and gross and microscopic histological examinations. RESULTS: Anastomotic leakage did not occur in either group. The operative time to complete the anastomosis for magnamosis (4.12 ± 1.04 min) was significantly less than that needed for manual suture (24.47 ± 4.89 min, P < 0.01). The portal vein pressure in the magnamosis group was more stable than that in the manual suture group. The blood ammonia level at the end of the 24-week post-implantation observation period was significantly lower in the magnamosis group than in the manual suture group. Gross and microscopic histological examinations revealed that better smoothness and continuity of the vascular intima had been achieved via magnamosis than with manual suture. CONCLUSION: Magnamosis was superior to manual suture for the creation of a portacaval shunt in this canine model of portal hypertension.

Extrahepatic portacaval shunt via a magnetic compression technique: A cadaveric feasibility study.

AIM: To explore the anatomical feasibility of portacaval shunt using a magnetic compression technique (MCT) in cadavers. METHODS: Computed tomography (CT) images of 30 portal hypertensive patients were obtained. The diameters of the portal vein (PV), the inferior vena cava (IVC), and distance between the two structures were measured. Similar measurements were performed on 20 adult corpses. The feasibility of portacaval shunt based on those measurements was analyzed. First stage of the extrahepatic portacaval shunt using MCT was performed on five cadavers. Specifically, the PV and IVC were exposed through an abdominal incision of the cadavers. The parent magnet was introduced from the femoral vein and was delivered into the IVC by an anchor wire and a 5F Cook catheter. The daughter magnet was introduced into the PV through the splenic vein using an interventional guide wire. When the daughter magnet met the parent magnet, they automatically clipped together and the first stage of the portacaval shunt was set up. RESULTS: The average diameters of the PV and the IVC measured from the 30 CT image were 14.39 ± 2.36 mm and 18.59 ± 4.97 mm, respectively, and the maximum and minimum distances between the PV and the IVC were 9.79 ± 4.56 mm and 9.50 ± 4.79 mm, respectively. From 20 cadavers, the average diameters of the PV and the IVC were 14.48 ± 1.47 mm and 24.71 ± 2.64 mm, and the maximum and minimum distances between the PV and the IVC were 10.14 ± 1.70 mm and 8.93 ± 1.17 mm, respectively. The distances between the PV and the IVC from both the CT images and the cadavers were within the effective length of portacaval anastomosis using MCT (30.30 ± 4.19 mm). The PV and IVC are in close proximity to each other with no intervening tissues or structures in between. Simulated surgeries of the first stage using MCT on five cadavers was successfully performed. CONCLUSION: Anatomically, extrahepatic portacaval shunt employing MCT is highly feasible in humans.

[The development of extrahepatic portacaval shunt device based on magnetic compression technique through the interventional procedure].

A device of extrahepatic portacaval shunt is introduced. This device is composed of the daughter and parent magnets and the vascular interventional operation equipment. It is based on the principle of magnetic compression technology, through the intervention approach the daughter and mother magnet are moved to the portal vein and inferior vena cava, respectively. Then the two magnets attract and compress the vessel walls of portal vein and inferior vena cava. Two weeks later, the magnets are detached from the vessel wall with a RUPS-set and the portacaval shunt is established. It is mainly used for the treatment of portal hypertension. It belongs to the interventional operation, there is no any foreign body remaining after the portacaval shunt is established, which can maintain long-term patency. Futhermore the portacaval shunt will not be expanded, therefore it can significantly reduce the incidence of hepatic encephalopathy.

The use of Dacron graft for cavo-cavostomy in orthotopic liver transplantation.

The end-to-end "interposition" technique and end-to-side "piggyback" technique are standard approaches to in situ anastomosis during orthotopic liver transplantation. We demonstrate that anastomosis of liver allograft to a Dacron vena cava graft can be a feasible solution if traditional anastomoses cannot be used. A 55-year-old man with end-stage liver failure from alcoholic cirrhosis underwent orthotopic liver transplantation; however, an intraoperative complication during recipient hepatectomy rendered the native vena cava unsalvageable. In addition, the donor vena cava was too short to bridge the caval defect for interposition. We therefore used Dacron for an in situ graft to span the gap, with subsequent anastomosis of the allograft to the prosthetic graft in piggyback fashion. The patient did well postoperatively; his only major complication was late anastomotic stenosis, which was treated successfully with balloon dilatation. Unfortunately the patient became recidivous and expired ten months posttransplant, despite indications of satisfactory allograft function.

Direct intrahepatic portocaval shunt.

The direct intrahepatic portacaval shunt (DIPS) is a modification of the TIPS procedure, using intravascular ultrasound-guidance, combined with fluoroscopy. The DIPS procedure was initially conceived to increase the durability of shunt patency and extend the spectrum of patients with portal hypertension for whom endovascular portocaval shunting can be performed. The DIPS procedure involves intravascular ultrasound-guided puncture from the inferior vena cava to the portal vein through the caudate lobe of the liver. The shunt is completed with a polytetrafluoroethylene-covered stent graft. This article describes the indications, technique, and outcomes of the DIPS procedure to enable the interventional radiologist currently experienced with TIPS to incorporate this procedure into their practice.

Survival and variceal rehemorrhage after shunting support small-diameter prosthetic H-graft portacaval shunt.

This study was undertaken to report variceal rebleeding and survival after small-diameter prosthetic H-graft portacaval shunts (HGPCS) and to compare actual to predicted survival after shunting. Since 1987 we have prospectively followed patients after undergoing HGPCS to treat bleeding varices failing/not amenable to sclerotherapy/banding. One hundred and seventy patients underwent shunting. Cirrhosis was because of alcohol in 56%, hepatitis in 12%, both in 11%, and other causes in 21%. Child class was A for 10%, B for 28%, and C for 62%. Thirty-three patients died by 6 months, 54 by 24 months, 87 by 60 months, and 112 by 10 years, generally because of liver failure. Fifty-one patients are alive at a median of 48.3 months, 76 months +/- 57.8 (mean +/- SD). Variceal rehemorrhage was documented in 3 (2%) patients. By child class, 5-year/10-year survival rates were as follows: A 66.7/33.3%, B 48.6/15.6%, and C 29.2/7.0%. Actual survival was superior to predicted survival (Model for End-Stage Liver Disease [MELD]), (p < 0.001). Variceal rehemorrhage in patients undergoing small-diameter prosthetic H-graft portacaval shunting was very uncommon. Actual survival was superior to predicted survival (MELD). Long-term survival paralleled degree of hepatic function, although long-term survival was possible even with very advanced cirrhosis. Application of HGPCS is encouraged.

Transvenous extrahepatic portacaval shunt with use of a modified prototype stent-graft: experimental study in animals.

PURPOSE: To evaluate the safety and short-term patency of an experimental transvenous extrahepatic portacaval shunt (TEPS) in an animal model. MATERIALS AND METHODS: With use of intravascular ultrasound (IVUS) guidance, the main portal vein (PV) was accessed from the inferior vena cava in six pigs and a TEPS was created with use of a prototype flanged stent-graft. Partial PV embolization was then performed to increase the post-TEPS PV pressure. Baseline and postprocedural hemoglobin and hematocrit measurements were obtained and liver function studies were conducted. Immediate postprocedural computed tomography (CT) of the abdomen was used to identify procedural complications. Follow-up venography was performed at 2, 4, and 12 weeks to assess short-term patency. Necropsy was performed at 3 months. RESULTS: IVUS-guided PV access was accomplished with a mean of two punctures per animal (range, 1-4). TEPS creation was successful in five of six animals. One animal was killed immediately after unsuccessful shunt creation after stent-graft misdeployment and hemorrhage. A second animal required the insertion of a conventional stent coaxially because portions of the leading arms were inadvertently deployed in the portacaval space and the initial flow through the shunt was venographically suboptimal. CT images obtained after successful TEPS creation (n = 5) revealed no evidence of hemoperitoneum, and there was no decrease in hemoglobin or hematocrit levels from baseline values. All five TEPSs were widely patent at 2-week and 4-week venography with only mild pseudointimal hyperplasia (<50% diameter stenosis) identified in one shunt. Twelve-week venography and necropsy demonstrated no evidence of shunt stenosis in one animal, less than 50% diameter stenosis in one animal, 50%-75% diameter stenosis in two animals, and shunt occlusion in one animal. CONCLUSION: Early results with TEPS with use of a modified prototype flanged stent-graft are promising as a potentially safe alternative means of portal decompression. Additional refinements of the stent-graft delivery process are needed to improve the accuracy of deployment.

Intravascular ultrasound-guided direct intrahepatic portacaval shunt: description of technique and technical refinements.

PURPOSE: This is a prospective study designed to demonstrate the safety and feasibility of creating a direct inferior vena cava (IVC)-to-portal vein shunt with use of a new type of intravascular ultrasound (IVUS) to guide the puncture and completing the shunt with the use of a polytetrafluoroethylene (PTFE)-covered stent graft. MATERIALS AND METHODS: IVC-to-portal vein shunts were created in 31 sequential patients for ascites (n = 31) or bleeding (n = 8). Transfemorally placed IVUS transducers were positioned in the IVC to guide the puncture from the IVC to the portal vein, which was performed from a transjugular approach with a modified Rosch-Uchida liver access set. A 9-MHz axial imaging IVUS system was used for the first 11 patients, and a variable 5-10-MHz sagittal IVUS imaging system was used for the next 20 patients. The shunts were completed with the use of single (n = 11) or overlapping (n = 20) PTFE-covered Palmaz stent-grafts, deployed primarily at a diameter of 8 mm. Patients were followed clinically and with US, venography, and inspection at liver transplantation to establish 30-day patency rates. RESULTS: All direct intrahepatic portacaval shunts (DIPSs) were created successfully. Both IVUS systems were able to adequately guide the portal vein puncture. Resolution and operator confidence were subjectively superior with the sagittal IVUS imaging system compared to the axial IVUS system. Two extrahepatic portal vein punctures occurred during the procedures. Both were controlled by the placement of sheaths and subsequent placement of stent-grafts. Both patients remained asymptomatic, although one required transfusion of blood products. The mean portosystemic gradient was reduced from 24 mm Hg before DIPS creation to 10 mm after DIPS creation. Embolization of varices was also performed in eight patients with history of recent gastrointestinal bleeding. Two patients died in the first week of acute liver failure. Two patients with hepatocellular carcinoma refused further follow-up. Of the 27 remaining patients, patency was demonstrated in all DIPS at 30 days by US, venography, or direct inspection at liver transplantation. CONCLUSIONS: IVUS-guided direct IVC-to-portal vein shunts may be created successfully with minimal complications. The use of a stent-graft is recommended for this procedure. Modifications of current technique and IVUS systems are described.

Effectiveness of porto-intracaval shunt to reduce the negative effects of portal and caval clamping in the rabbit.

In performing experimental liver surgery, it is difficult to prolong anhepatic time because the animals do not tolerate prolonged portal and caval clamping. To counteract prolonged venous stasis, the authors previously developed a simple porto-intracaval shunt. The shunt consists of a self-constructed inverted Y silicone tube. The effectiveness of this shunt was studied comparing two groups of 10 rabbits with shunt (S) versus those with clamped portal and inferior caval vein (C). In the group of rabbits that underwent porto-intracaval shunt, the results concerning intraoperative mortality, intraoperative increase in distal portal vein pressure, and incidence of the histologic signs of gut damage were clearly improved. The proposed porto-intracaval shunt was therefore effective in reducing some principal negative effects of portal and caval clamping. This type of porto-intracaval shunt can be therefore useful allowing improvement of experimental models concerning liver surgery in little animals.

Intravascular US-guided direct intrahepatic portacaval shunt with a PTFE-covered stent-graft: feasibility study in swine and initial clinical results.

PURPOSE: To determine the feasibility of the creation of a direct intrahepatic inferior vena cava (IVC)-to-portal-vein shunt with puncture guided by a transfemorally placed intravascular ultrasound (IVUS) probe and use of a polytetrafluoroethylene (PTFE)-covered stent-graft. MATERIALS AND METHODS: In five swine, transjugular access was used to perform a direct puncture from the IVC to the portal vein with use of a modified Rosch-Uchida Portal Access set directed with real-time IVUS (9 MHz) introduced from a transfemoral venous approach. The direct intrahepatic portocaval shunt (DIPS) was then created with single or overlapping PTFE-covered Palmaz stents placed through a 10-F sheath and dilated to a diameter of 8 mm. Follow-up was performed with transhepatic portography at 2, 4, and 8 weeks. Animals were killed when shunts occluded or at the termination of the study at 8 weeks. Gross and microscopic histologic study was performed on sacrificed animals. A similar technique was used to create DIPS in five patients with intractable ascites, with follow-up by US and venography. RESULTS: All experimental DIPS created in swine were created without complications. Portal vein punctures were achieved in four of five swine on the first or second pass of the needle. Follow-up transhepatic portography at 2 weeks demonstrated occlusion of two shunts, both explained by technical reasons at sacrifice. At 4 and 8 weeks, the remaining three shunts were patent on portography. Histology showed a thin neointimal lining with no significant tissue ingrowth or hyperplasia. Clinically, in five patients, successful puncture of the portal vein from the IVC was achieved in one to three passes. Creation of DIPS led to a reduction of mean portosystemic gradient from 18-29 mm Hg (mean, 24 mm Hg) to 9-10 mm Hg (mean, 9 mm Hg). One patient died of liver failure 2 days after creation of DIPS. The other four patients were doing well 2-15 months (mean, 8 months) after the procedure, with patency confirmed by US and venography. CONCLUSION: Creation of DIPS is technically feasible, and the direct IVC-to-portal-vein puncture can be done accurately with real-time IVUS guidance. Further studies and longer follow-up are necessary to determine if the short length of the PTFE-covered stent-graft and avoidance of the hepatic vein will increase the long-term patency compared to standard transjugular intrahepatic portosystemic shunt creation.

Nurses, surgeon not negligent in retained instrument suit. Kissinger v Turner.

Instrument counts are controversial. Though they are recommended on all procedures by the Association of Operating Room Nurses, the majority of hospitals aren't doing them, according to a survey by OR Manager. What happens if you don't have a policy, an instrument is left in, and the case goes to court? What is the role of professional recommendations? The health care law firm of Horty, Springer & Mattern discusses just such a case.