Hepatic Venous System Research Articles

Development of catheter-based procedures for transducing the isolated rabbit liver with plasmid DNA.

Rapid systemic injection of naked plasmid DNA (pDNA) in a large volume into a mouse tail vein has been shown to result in a high level of gene expression in the liver. However, the potential therapeutic benefit to humans embodied in hydrodynamic transfection of the liver cannot be realized until a clinically viable method for gene delivery is developed. In light of this fact, we have devised and evaluated several methods for delivering pDNA to the isolated rabbit liver using minimally invasive catheter-based techniques. Using a lobar technique, pDNA was delivered hydrodynamically to an isolated hepatic lobe using a balloon occlusion balloon catheter to occlude a selected hepatic vein. A whole organ technique was used wherein the entire hepatic venous system was isolated and the pDNA solution injected hydrodynamically into the vena cava between two balloons used to block hepatic venous outflow. Lobar delivery of a plasmid encoding a secreted alkaline phosphatase (SEAP) reporter gene resulted in significant levels of transgene product in the serum. A nonsecreted transgene product, chloramphenicol acetyltransferase (CAT), showed the highest levels of expression in the injected lobe distal to the injection site. Compared to lobar delivery, whole organ delivery yielded much higher serum levels of SEAP expression and a significantly broader hepatic parenchymal distribution of CAT expression. These preliminary studies suggest that catheter-mediated hydrodynamic delivery of pDNA to the isolated liver may provide a method for human gene therapy that is both therapeutically significant and clinically practicable.

Reproposal for Hjortsjo's Segmental Anatomy on the Anterior Segment in Human Liver

A minimum, but necessary amount, of cancer-containing liver tissue is to be excised in patients who have poor liver function. To achieve that goal of excision, a limited hepatic resection has been carried out. However, performing subsegmentectomy of the anterior segment according to the conventional segmental anatomy introduced by Healey and Schroy or Couinaud is difficult. Because the transverse border between segments 5 and 8 was drawn as an imaginary line through the right portal vein, there is no anatomical structure indicating this border. Hjortsjo divided the anterior segment into 2 vertical segments according to the fissure in which a hepatic vein coursed. By including Hjortsjo's concept of segmental anatomy, new procedures will be added to hepatic surgery. Sixty-five cadaveric livers were dissected to confirm Hjortsjo's concept of segmental anatomy by investigating the vertical fissure that divides the anterior segment into 2 areas, concerning the relation between portal segmentation and the hepatic venous system of the anterior segment. The territories of the third-order portal branches of the anterior segment were divided into 2 (ventral and dorsal) areas with a vertical fissure and in its intersubsegmental plane, an independent hepatic vein, or a first-order branch of the middle or the right hepatic vein coursed. These findings confirmed the certainty of Hjortsjo's concept of segmental anatomy of the anterior segment. This is relevant for developing new procedures in hepatic surgery. Its reproposal is opportune for adding it as another concept to the conventional segmental anatomy.

Right-lobe living related liver transplantation: evaluation of a comprehensive magnetic resonance imaging protocol for assessing potential donors.

The purpose of this study was to determine the practicability and diagnostic accuracy of a magnetic resonance (MR) protocol capable of replacing computed tomography, catheter angiography, and endoscopic retrograde cholangiopancreatography for the presurgical evaluation of potential liver donors before right hepatectomy. MR imaging (MRI) was performed on a 1.5 T scanner using a phased-array torso surface coil for signal reception. The following image sets were collected: axial two-dimensional (2D) T1-weighted fast low angle shot (FLASH), axial 2D T2-weighted half-Fourier acquisition single-shot turbo-spin-echo (HASTE) with fat saturation, coronal MR cholangio-pancreatography (MRCP) based on 2D multisection HASTE and single-section single-shot rapid acquisition with relaxation enhancement (RARE) imaging, dynamic contrast-enhanced three-dimensional (3D) FLASH, and contrast-enhanced T1-weighted FLASH. 3D FLASH data sets were collected before and after an intravenous administration of Multihance (gadobenate dimeglumine, Gd-BOPTA; Bracco, Milano, Italy), 0.2 mmol/kg of body weight. Thirty-eight potential liver donors were assessed by means of MRI. Twenty patients also underwent digital subtraction angiography (DSA). Of these, 16 patients underwent liver harvesting. MR angiography (MRA) data sets correlated with DSA results, and MRCP results correlated with intraoperative findings. Patients were excluded as potential donors based on insufficient liver mass of the left hepatic lobe (n = 5) or presence of hepatic pathological states (n = 9) seen at MRI, such as hemangiomas, focal nodular hyperplasias, or hepatic steatosis. MRCP showed the biliary system to the level of the first hepatic side branch. Dilated ducts were present in 4 patients. MRA depiction of hepatic arterial morphological characteristics correlated with catheter angiography results in all 20 patients: Three left hepatic arteries originating from the left gastric artery, three aberrant right hepatic arteries originating from the superior mesenteric artery, and two aberrant origins of both hepatic arteries and one common hepatic artery originating from the superior mesenteric artery were correctly identified on MRA. Similarly, the portal venous system was fully assessed on MRA. A comprehensive assessment of the hepatic parenchyma, biliary and pancreatic ductal system, and hepatic arterial, portal, and venous systems can be accomplished using the outlined protocol.

The anatomy of the umbilical, portal and hepatic venous systems in the human fetus at 14-19 weeks of gestation.

Ultrasound imaging of the fetal ductus venosus is becoming increasingly commonplace in clinical practice. The true anatomical relationships of the fetal umbilical and portal venous systems have not been clearly defined due to paucity of published data on the relevant anatomy. This has led to confusing terminology when describing the fetal umbilical, portal and hepatic circulations. The aim of the present study was to examine and document the anatomy of the umbilical, portal and hepatic venous systems and to propose a standardized nomenclature. This was a prospective study on 11 fetuses obtained from medical termination of pregnancies between 14 and 19 weeks of gestation. The liver was microdissected to expose the branching pattern and anatomical relations of the umbilical, portal and hepatic venous systems. A wide L-shaped venous confluence at the terminal end of the umbilical vein, termed the portal sinus, was identified. The portal sinus was connected to the right and left hepatic lobes, by the right and left intrahepatic portal veins, respectively. The extrahepatic portal vein drained into the portal sinus just before the origin of the right intrahepatic portal vein. The ductus venosus, a branchless straight vessel, originated from the portal sinus and ascended steeply in the direction of the diaphragm. Numerous small vessels draining the liver converged into three main hepatic veins, which open into the subdiaphragmatic vestibulum. Based on detailed sequential anatomical dissection and clear illustrations, the present study documents the anatomy of the umbilical, portal and hepatic venous systems. Taking into account the embryological origin of the vessels, a new anatomically appropriate and simplified nomenclature of these venous systems is proposed. In clinical practice, the consistent use of the suggested terminology would allow collection of comparable data between units and enable operators to be confident of which vessels they are sampling by Doppler ultrasound.

F58Anatomical variation of the fetal venous system

ObjectiveThis report presents our experience in the prenatal diagnosis of anomalies of fetal veins using high‐resolution and color Doppler ultrasound.DesignIn an observatorial study 15 cases of abnormalities of the umbilical, portal, hepatic and caval venous system have been diagnosed at our division over the past 5 years. The abnormality, the underlying embryologic disorder and the outcome of the pregnancy are presented.ResultsIn group A, 8 fetuses had an abnormal course of the umbilical vein with a patent (n = 3) or absent (n = 5) ductus venosus. No portal veins and absent or abnormal hepatic veins were visualized. Six fetuses (75%) did not have an associated malformation and have survived. Two pregnancies were terminated or ended in fetal demise. In group B, 7 fetuses with an abnormal caval system had a left (n = 5) and right (n = 2) atrial isomerism with a cardiac defect in 6 cases (86%). The pregnancies ended in 4 terminations of pregnancy and two infant deaths. Only an infant with a left atrial isomerism and a normal heart has survived.ConclusionIn a targeted fetal scan the course of the venous system should be carefully examined using color Doppler. Any suspicious finding should be followed by a detailed assessment of the specifity of this abnormality considering the embryological development as well as the associated malformations.

Clinical use of Levovist, an ultrasound contrast agent, in the imaging of liver transplantation: assessment of the pre- and post-transplant patient.

Colour Doppler US is well established for imaging of hepatic vessels in the assessment of pre- and post-liver transplant patients. Unfortunately, a full colour Doppler US examination of the portal or hepatic venous and hepatic arterial systems is frequently precluded by technical factors. Ultrasound contrast agents are useful in enhancing vascular Doppler signal and play an important role in liver transplantation assessment. A series of patients with vascular problems illustrates the role of US contrast in the pre-transplant candidate, where portal vein patency and direction of flow is assessed, presence of portal vein thrombus is confirmed and cavernous transformation demonstrated. Occlusion of hepatic veins in Budd-Chiari syndrome is confidently confirmed. Following liver transplantation, US contrast allows a comprehensive assessment of hepatic artery thrombosis, hepatic artery stenosis and pseudoaneurysm formation. The need for further imaging is reduced or confidently deferred in many instances. Ultrasound contrast agents play an important role in the liver transplant candidate.

Prenatal diagnosis of abnormalities of the fetal venous system.

To present our experience in the prenatal diagnosis of anomalies of fetal veins using high-resolution color Doppler ultrasound. An observational study of 16 fetuses with abnormalities of the umbilical, portal, hepatic and caval venous system being diagnosed at the Division of Prenatal Diagnosis and Therapy (Bonn, Germany) over the past 5 years. The abnormality of the venous system, the underlying embryologic disorder and the outcome of the pregnancy are presented and compared with the literature. In group A, eight fetuses had an abnormal course of the umbilical vein with a patent (n = 3) or absent (n = 5) ductus venosus. No portal veins and absent or abnormal hepatic veins were visualized by color Doppler sonography. Six fetuses (75%) did not have an associated malformation and have survived. Two pregnancies with fetal hydrops due to a small heart and to Turner's syndrome were terminated or ended in fetal demise. In group B, seven of eight fetuses with an abnormal caval system had a situs ambiguus or an atrial isomerism. A cardiac defect was detected in six cases (86%). These six pregnancies ended in four terminations of pregnancy and two infant deaths due to the severity of the congenital cardiac defect. One child with a normal heart and a child with an isolated abnormal course of the lower inferior vena cava are developing well. In a targeted fetal scan the course of the umbilical vein, ductus venosus, the portal and hepatic veins and inferior vena cava should be carefully examined using color Doppler. Any suspicious finding should be followed by a detailed assessment of the specificity of this abnormality taking into consideration the embryologic development of the fetal venous system together with the associated malformations.

Relation among portal segmentation, proper hepatic vein, and external notch of the caudate lobe in the human liver.

To identify portal segmentation and a portal fissure in the caudate lobe of the human liver in relation to the hepatic venous system and the external notch at the caudal edge of the caudate lobe. Although the anatomy of the caudate lobe has been studied, the detailed anatomy has not yet been clarified; this is necessary to develop safe procedures for caudate lobe resection. A total of 88 formalin-fixed human livers were dissected to visualize the portal vein and hepatic vein systems of the caudate lobe in relation to the external notch. The patterns of portal branching were classified into two types. In 58 livers (67.4%), the territories of the first-order portal branches were clearly divided into two areas (the Spiegel lobe and the paracaval portion). In the remaining 28 livers (32.6%), the territories of the second-order portal branches were clearly divided into two areas. These two areas were distinctly separated by an internal plane, which was coincident with the external notch. The caudate lobe had a systematized hepatic venous system that consisted of one (87.5%) or two (11.4%) proper hepatic veins and plural accessory hepatic veins. The proper hepatic veins laid along the internal plane between these two portal areas. The caudate lobe exhibited distinct portal segmentation with a portal fissure that was indicated internally by the proper hepatic vein and externally by the notch at the caudal edge of the caudate lobe.

Hepatocanalicular Cholestasis after 24 Years of Azathioprine Administration for Myasthenia Gravis

Azathioprine hepatotoxicity has been described mainly in renal transplant recipients. Lesions of the hepatic venous system are often reported, namely peliosis hepatis, perisinusoidal fibrosis, venoocclusive disease and nodular regenerative hyperplasia (NRH) of the liver. The significant clinical correlation of these hepatic vascular lesions is portal hypertension. We present a patient who developed hepatocanalicular cholestasis with proliferation of the bile ducts after 24 years of azathioprine treatment for myasthenia gravis.

Role of transjugular intrahepatic portosystemic shunt in the treatment of portal hypertension in pediatric patients.

Role of transjugular intrahepatic portosystemic shunt in the treatment of portal hypertension in pediatric patients.

Development of a percutaneous fiberoptic hepatic venous localization catheter.

To develop a liver-specific biosensor system/catheter assembly that can be used to localize and cannulate the hepatic venous system without the need for fluoroscopic imaging. This would permit the bedside placement of a hepatic venous catheter for monitoring purposes without radiographic guidance. Experimental, in vitro. Experimental laboratory at a university center. This was a simulation study to evaluate the ability of a cardiovascular monitoring catheter mounted with a liver-specific biosensor to anatomically identify a side arm tributary. The experimental system used for this study mimics the hepatic vein draining into the inferior vena cava and allows its localization without the need for assisted imaging. The biosensor design and catheter/sensor assembly function were studied in this in vitro model. A liver-specific biosensor was developed by housing a homogeneous affinity fluorescence assay system sensitive to galactose in a microdialysis hollow fiber receptacle. A polyvinyl chloride tube containing a side arm was constructed to mimic the confluence of a venous tributary (i.e., the hepatic vein) with a major vascular channel (i.e., the vena cava). In this simulation, the side arm was continuously perfused with a liver-sensitive analyte (galactose) and the main channel was perfused with galactose-free buffer. A cardiovascular catheter containing a fiberoptic waveguide mounted with a galactose-sensitive fluorescent probe was advanced along the main conduit to assess its ability to identify the location of the galactose side arm infusion site. The response of the fiberoptic sensor to different galactose concentrations was assessed and found to be almost linear over the concentration range of 0 to 2 mM, which encompasses the expected utilization range of this system. The variability in identifying the galactose infusion point (simulated hepatic vein) in a 15-cm conduit was 1.7 to 2.8 mm, or 1.1% to 1.9%. The construction of a catheter/sensor system with the ability to provide accurate spatial/anatomical localization data for the hepatic venous system is feasible. This assembly will eliminate the need for ancillary imaging systems for catheter/sensor delivery to an individual organ system and potentially can be positioned at the bedside in a fashion similar to the pulmonary artery flotation catheter.

Magnetic resonance of the hepatic veins with angular reconstruction: application in living-related liver transplantation.

Preoperative mapping of the hepatic venous system of the partial liver graft is indispensable to the success of living-related liver transplantation. We assessed the accuracy of magnetic resonance (MR) venography with angular reconstruction in depicting the tributaries of the middle hepatic vein and left hepatic vein in the donors, which was essential in graft retrieval and venoplasty. Nineteen living-related liver transplantation donors underwent a pretransplantation survey, including sonography and MRI for hepatic venous evaluation. T1-weighted images were reconstructed manually, using the inferior vena cava as a fixed point for tilting to produce an oblique plane image where both the middle hepatic vein and left hepatic vein could be demonstrated draining into the inferior vena cava. The reconstructed images of the hepatic veins were compared with preoperative sonography, intraoperative sonography, and operative findings. Preoperative sonography and MR findings correlated well with the operative findings in the major hepatic veins. The MR venography of the ramification of the hepatic veins has an accuracy of 93%, the sonography, 84%. Sonography is slightly inferior in the evaluation of the hepatic vein in segment 4 and the left superior hepatic vein, with an accuracy of 73% and 67%, respectively. MR venography with angular reconstruction is accurate in depicting the complex distribution of the hepatic veins of the left liver, providing important information for decision making as to the cutting plane during graft retrieval and the method of venoplasty and anastomosis. Thus, unnecessary blood loss could be avoided and vascular complications could be prevented, as these conditions would be unacceptable for a healthy living donor. We propose that MR venography, a rapid and reliable technique, is an appropriate alternative examination or complementary modality to sonography in the pretransplantation evaluation of the living donor.

A CASE OF NON-OCCLUSIVE MESENTERIC ISCHEMIA ASSOCIATED WITH PORTAL VENOUS GAS

We report here the case of an 81-year old male referred to our hospital with abrupt onset severe abdominal pain. Physical examination showed severe abdominal tenderness with mild rebound tenderness and rectal tumor was palpable on digital examination. Abdominal computed tomography revealed ascites with a thickened small intestinal wall and gas in the hepatic portal venous system. Superior mesenteric arteriography revealed irregular strictures without arterial occlusion. A diagnosis of ischemic enteritis was determined, and an emergency laparotomy was performed. Resection of a 100cm long segment of necrotic ileum, and a looped colostomy of the sigmoid colon were perfomed. The patient was discharged on the 61th postoperative day after receiving radiation therapy for rectal cancer. We made the diagnosis of non-occlusive mesenteric ischemia from the findings of arteriography. No evidence of arterial diseases was found in the resected specimens. Indications for operation should be carefully decided because portal venous gas accompanys ischemic bowel, as well as other diseases.

Identification of segments VI and VII of the liver based on the ramification patterns of the intrahepatic portal and hepatic veins.

We describe the pattern of intrahepatic vessel ramification in the right posterior hepatic sector in a population of 197 adults. Each specimen was dissected from its visceral (inferior) surface in order to demonstrate variations in the distribution of the portal vein branches to the hepatic segments of the right lobe, especially to segments VI (S6) and VII (S7) as described by Couinaud. We also examine whether three hepatic veins, i.e., the right hepatic vein (RHV), middle hepatic vein (MHV), and the short hepatic vein (SHV), aid the identification of segmental portal branches in the lower posterior sector. Four major patterns of branching of the posterior sectorial trunk of the portal vein system are described. In group A (32.0%) a single posterior trunk formed an arch-like pattern sending multiple branches to S6 and S7 (P6 and P7). We named the multiple branches to the apparent S6 the inferoposterior portal branches. It was difficult to identify which of these branches were equivalent to P6. In group B (27.9%), the posterior sectorial trunk bifurcated to form P6 and P7. In most of the specimens in this group, therefore, we were able clearly to identify both S6 and S7 based on the portal vein system. In group C (6.6%), the trunk trifurcated to form P6, P7, and an intermediate branch, which supplied both segments or a gray zone between them. Group D (33.5%) included variations of the anterior segmental branches, and in specimens of this group, the anteromedial border of the sector was difficult to identify. Notably, the three-dimensional interdigitating topographical relationship of the hepatic veins and the portal branches was not evident in the lower posterior sector, since tributaries of the RHV and the portal branches followed similar courses and paralleled each other in the region and since the territory of the SHV was usually restricted to the superficial parenchyma near the inferior surface. In group A, tributaries of the RHV/SHV (>3 mm in diameter) passed between the inferoposterior portal branches in only 22.2%/14.3% of the specimens. Thus the hepatic veins often did not reveal which of the multiple inferoposterior branches was P6. Moreover, in the subset of Group B in which the segments were identified based on the portal vein ramification, tributaries of the RHV/SHV (>3 mm in diameter) showed the intersegmental interdigitating arrangement in only 32.0%/6.0% of the specimens. In addition, a thick tributary of the MHV, sometimes arising from S6, did not run along, but penetrated the S5/S6 border plane from the lateral to the medial side. Therefore, the three hepatic veins (RHV, SHV, MHV) often did not aid the identification of the liver segments in the region. Consequently, the less than ideal combinations of irregular configurations of the portal and hepatic venous systems suggest that the right posterior segments cannot be conclusively identified anatomically in 30-40% of cases. Other means of identification, such as the conventional proportional manner (the upper and lower halves of the posterior sector roughly correspond to S6 and S7) may be required.

Intrahepatic Venous Anato my on Three-Dimensional Spiral CT during Arterial Portography

Purpose: To evaluate the intrahepatic anatomy of the hepatic vein and right portal venous system, as seen on 3-D CTAP, and to assess the avascular zone between the anterior and posterior segments of the right lobe in relation to the right hepatic vein. Materials and Methods: Fifteen patients in whom nodular hepatocellular was suspected underwent spiral C-TAP. 3-D images of the portal and hepatic vein were obtained using the maximal intensity projection technique. We examined the portal venous branching pattern and the draining pattern of the hepatic venous system to the inferior vena cava, as well as variation of the right hepatic vein and the avascular zone between the anterior and posterior segments of the right lobe. Results: In 13 patients, three hepatic veins were clearly visualized, and in ten, the middle and left hepatic veins conjoined before draining to the IVC. In three patients, three hepatic veins drained separately into the IVC. Two right hepatic veins were seen in three patients. The right portal venous system was clearly visualized in 13 patients a classical branching pattern in 11, trifurcation in one, and four simultaneous branching patterns in one. Lateral projection showed that the angle of the avascular zone declined posteriorly by 26- 64( 47.5) in relation to the right hepatic vein. Conclusion: We observed the drainage pattern of the hepatic vein and variation of the right portal venous system on 3-D image, and confirmed that since the avascular zone declined posteriorly, the right hepatic vein is an inappropriate landmark for right hepatic segmentation.

Anatomy relevant to TIPS

Understanding the anatomy of the hepatic vasculature is a key element to safe and successful transjugular intrahepatic portosystemic shunts (TIPS) performance. In this article, the normal anatomy of the hepatic and portal venous system is reviewed, and the relationship between these vessels is discussed. Misidentification of the hepatic or portal vein can lead to procedural complications and possibly compromise the success of the procedure. Common anatomic pitfalls in TIPS are discussed and illustrated. New procedural modifications designed to minimize or prevent TIPS stenosis are currently under investigation. The anatomic constraints of these new approaches are discussed.

Role of Adenosine in the Cardiac Catheterization Laboratory

Adenosine is a direct and potent mediator of vasorelaxation in most vascular beds except in the renal efferent arterioles and hepatic venous system, where it causes vasoconstriction. Adenosine appears to exert its vasodilating effects through activation of membrane receptors. Dipyridamole has indirect vasodilatory effects by inhibiting cellular re-uptake and capillary endothelial transport of endogenously produced adenosine. Adenosine and dipyridamole act more selectively on the small arterioles than on the larger epicardial vessels.

Systemic and hepatic hemodynamic changes in acute liver injury.

Systemic and hepatic circulatory changes were studied in rats over the course of acute liver injury. Hepatic injury was induced by intraperitoneal injection of D-galactosamine (1.1 g/kg), and systemic and hepatic hemodynamics were measured over a 72-h period using a radioactive microsphere technique with direct measurement of arterial, portal venous, and hepatic venous blood oxygen content. Cardiac output increased to a maximum at 48 h, producing a marked increase (450%) in hepatic arterial blood flow so that it became the dominant supply of oxygen at the time of maximal hepatic injury. A subsequent increase in portal venous flow resulted in an overall increase in total hepatic blood flow of 500%. At this point the oxygen delivery by the hepatic arterial and portal venous systems was equal. These circulatory changes returned to control values by 72 h with recovery of liver function. These results demonstrate the development of a hyperdynamic circulation and a marked change in the normal relationship between portal venous and hepatic arterial blood flows that occur during hepatic injury.

The effect of intravascular blood transfusion on the flow velocity waveform of the hepatic venous system of the anemic fetus

The effect of intravascular blood transfusion on the flow velocity waveform of the hepatic venous system of the anemic fetus

A homogeneous affinity fluorescence assay system for galactose monitoring

Since the systemic venous-hepatic venous galactose gradient is normally quite large, the ability to detect different blood galactose concentrations in vivo would provide a mechanism for anatomic localization of the hepatic venous system. Furthermore, the development of a catheter assembly mounted with a galactose-sensitive biosensor would provide a technique for cannulating this organ system entirely using sensor guidance. In this report we describe a homogeneous affinity fluorescence assay system which can be contained in a dialysis hollow fiber for continuous galactose monitoring. The principle of this assay is based upon competition of freely permeable galactose for the specific binding interactions between a fluorescently labeled polysaccharide and lectin reagent pair. This competetive energy-transfer assay exhibits good sensitivity over a physiologically relevant galactose concentration range (0–2 mM), an acceptable response time (<200 s) and small dimensions, which make it potentially adaptable to conventional catheter systems for in vivo use. Such a system would greatly simplify diagnostic efforts to evaluate hepatic function in real time.