Liver cirrhosis in hepatic vena cava syndrome (or membranous obstruction of inferior vena cava)

Hepatic vena cava syndrome (HVCS) also known as membranous obstruction of inferior vena cava reported mainly from Asia and Africa is an important cause of hepatic venous outflow obstruction (HVOO) that is complicated by high incidence of liver cirrhosis (LC) and moderate to high incidence of hepatocellular carcinoma (HCC). In the past the disease was considered congenital and was included under Budd-Chiari syndrome (BCS). HVCS is a chronic disease common in developing countries, the onset of which is related to poor hygienic living condition. The initial lesion in the disease is a bacterial infection induced localized thrombophlebitis in hepatic portion of inferior vena cava at the site where hepatic veins open which on resolution transforms into stenosis, membrane or thick obstruction, and is followed by development of cavo-caval collateral anastomosis. The disease is characterized by long asymptomatic period and recurrent acute exacerbations (AE) precipitated by clinical or subclinical bacterial infection. AE is managed with prolonged oral antibiotic. Development of LC and HCC in HVCS is related to the severity and frequency of AEs and not to the duration of the disease or the type or severity of the caval obstruction. HVOO that develops during severe acute stage or AE is a pre-cirrhotic condition. Primary BCS on the other hand is a rare disease related to prothrombotic disorders reported mainly among Caucasians that clinically manifest as acute, subacute disease or as fulminant hepatic failure; and is managed with life-long anticoagulation, porto-systemic shunt/endovascular angioplasty and stent or liver transplantation. As epidemiology, etiology and natural history of HVCS are different from classical BCS, it is here, recognized as a separate disease entity, a third primary cause of HVOO after sinusoidal obstruction syndrome and BCS. Understanding of the natural history has made early diagnosis of HVCS possible. This paper describes epidemiology, natural history and diagnosis of HVCS and discusses the pathogenesis of LC in the disease and mentions distinctive clinical features of HVCS related LC.     

Budd-Chiari syndrome caused by membranous obstruction of the inferior vena cava associated with coeliac disease

Ten cases of Budd-Chiari syndrome associated with coeliac disease have been reported in the literature, most of them in North African subjects. Supporting this association, we report a new case in a young Spanish Caucasian man in whom the cause of the syndrome was the membranous obstruction of the inferior vena cava, an infrequent cause of Budd-Chiari syndrome in Western countries. A percutaneous balloon angioplasty was performed, with satisfactory outcome.     

Endemicity and clinical picture of liver disease due to obstruction of the hepatic portion of the inferior vena cava in Nepal

Obstructive lesion of the hepatic portion of the inferior vena cava is common in Nepal. The clinical data on 150 patients who were seen at the Liver Unit, Bir Hospital, Kathmandu, in three years from 1990 to 1992 were analysed. Although the majority of patients were over 20 years of age, 25 patients were below 10 years of age; there were more males than females in this study. This disease accounted for 17% of 866 patients with chronic liver disease and for nearly one quarter of 267 biopsies performed on this patient group during the same period. Obstructive lesions of the inferior vena cava seem to be more common among poor people with malnutrition. Clinically, our patient group could be divided into acute (n= 27), subacute (n= 43) and chronic (n= 80) cases. The important clinical features are hepatomegaly and/or ascites and, in chronic cases, prominent dilated superficial veins over the body trunk with cephalad flow. Ultrasound is the most helpful diagnostic procedure, especially in subacute and chronic cases, as it frequently demonstrates caval obstruction, thrombosis, dilated hepatic veins and intrahepatic collaterals. Diagnosis is confirmed by cavography, which shows a caval obstruction of varying lengths at the cavo-atrial junction or a marked narrowing of the hepatic portion of the vena cava. In subacute and chronic cases cavography also demonstrates collateral veins, such as the ascending lumbar, hemiazygos and azygos that drain into the superior vena cava. Chronic cases had periods of exacerbation often associated with bacterial infection. The aetiology of inferior vena cava obstruction at its hepatic portion is not known, but there seems to be a frequent association of bacterial infection with the disease.     

MDCT venography in the evaluation of inferior vena cava in Budd-Chiari syndrome

Objective  To assess the role of multidetector computed tomography (MDCT) venography in the evaluation of the inferior vena cava (IVC) in Budd-Chiari syndrome (BCS), its accuracy as compared to digital subtraction venography (DSV) and the potential of this technique to replace venography for the definitive diagnosis of BCS. Methods  Twenty-five suspected cases of BCS were prospectively enrolled in this study and underwent both MDCT venography and DSV. Two observers independently evaluated and graded both the axial and reformatted MDCT images for the presence, site, degree and length of IVC narrowing. The collateral pathways and the hepatic veins were also assessed in all cases. The degree of correlation between MDCT venography and DSV was expressed using Spearman’s rank correlation coefficient (Rs). Results  There was excellent correlation between MDCT venography and DSV in predicting the presence of stenosis and in grading the degree and length of IVC stenosis (Rs=0.58, p<0.05). Four patients had presence of a web within the IVC and the reconstructed MDCT venography images detected the flap of the membrane in all of them. In three cases of complete obstruction the cranial extent of the obstruction could be determined on the reconstructed MDCT venography images, while double catheter access through the femoral and jugular routes was needed to determine the same on DSV. MDCT venography was significantly more informative in depicting the presence and site of both intrahepatic and extrahepatic collaterals as compared to DSV. Conclusion  MDCT venography, in the present study, accurately provided information of both conventional CT and IVCgraphy, in the evaluation of the IVC in a non-invasive way. It helped overcome the shortcomings of CT in the evaluation of IVC and was better than DSV for the evaluation of collaterals, calcification and complete IVC obstruction. We suggest that CT venography can be used as a frontline investigation for the diagnosis of IVC obstruction and for planning surgery or percutaneous endovascular intervention.     

High prevalence of hepatitis B virus infection and inferior vena cava obstruction among patients with liver cirrhosis or hepatocellular carcinoma in Nepal

BACKGROUND: Little is known about the prevalence of hepatitis B virus (HBV) DNA and the genotype distribution among patients with liver diseases in Nepal, where obstruction of the hepatic portion of the inferior vena cava (IVCO) is common. The aim of the present paper was to assess the roles of HBV infection and IVCO in liver cirrhosis (LC) and hepatocellular carcinoma (HCC) in Nepal. METHODS: Serum samples from 121 patients (89 male, 32 female; age, 55.0 +/- 13.6 years) with or without IVCO consisting of 70 LC patients and 51 HCC patients in Nepal, were tested for HBV-DNA. RESULTS: The HBV-DNA was detected in 68 patients (56%) including 20 hepatitis B surface antigen (HBsAg)-negative patients: 33 LC patients (47%) and 35 HCC patients (69%) had detectable HBV-DNA (P = 0.0303). Among the 89 patients with IVCO, HBV-DNA was detected in HCC patients significantly more frequently than in LC patients (80%vs 43%, P = 0.0005). The frequency of HBV viremia was significantly higher among HCC patients with IVCO than those without (80%vs 44%, P = 0.0236), and that of HBV viremia with IVCO was significantly higher among HCC patients than among LC patients (55%vs 27%, P = 0.0153). The HBV genotypes A and D were predominant, and genotype A was significantly more frequent among HCC patients than among LC patients (22%vs 6%, P = 0.0090). Among HCC patients, those with genotype A HBV were significantly younger than those with genotype D (43 +/- 13 vs 57 +/- 12 years, P = 0.0252). CONCLUSION: Hepatitis B virus alone (especially genotype A) or in concert with IVCO may be responsible for development of HCC in Nepal.     

布-加综合征、肝血窦阻塞综合征与肝硬化的鉴别

布-加综合征是由肝静脉或其开口以上的下腔静脉阻塞性病变引起的以下腔静脉阻塞、门静脉高压为特点的综合征,诊断依靠影像学检查,治疗的关键是解除梗阻。肝血窦阻塞综合征是指肝窦内皮完整性破坏和肝窦内充血阻塞而产生的肝内窦后性门静脉高压症,临床表现类似布-加综合征,诊断依靠肝组织活检。这两种疾病的治疗和预后均与肝实质病变导致的肝硬化不同,所以临床上需要注意这三种疾病的鉴别。     

Balloon dilatation of inferior vena cava obstruction in budd-chiari syndrome

Budd-Chiari syndrome is a well described entity which can easily be confused with congestive hepatomegaly. The syndrome usually is caused by thrombosis of the hepatic veins, however it also can be caused by congenital fibrous webs that occlude hepatic vessels in the inferior vena cava. It leads to an enlarged liver with ascites, peripheral edema, and portal hypertension.     

Asymptomatic membranous obstruction of the inferior vena cava forming intrahepatic collateral pathways

Intrahepatic and/or extrahepatic collateral pathways result from the membranous obstruction of the inferior vena cava. These collaterals are usually insufficient to prevent Budd-Chiari syndrome. We reprot an unusual case of asymptomatic membranous obstruction of the inferior vena cava in which marked intrahepatic collateral pathways were formed. Although the inferior vena cava terminated above the orifice of the right hepatic vein, the middle and left hepatic veins were patent above the membrane, without narrowing. Blood from the inferior vena cava drained into the right atrium via the intrahepatic collaterals between the right and middle hepatic veins without resistance.     

Membranous obstruction of inferior vena cava in Taiwan

Abstract Membranous obstruction of the inferior vena cava (MOVC) is a rare cause of Budd-Chiari syndrome. When compared to the West, the incidence of MOVC was reported to be higher in the Orient, India and South Africa. From 1979 to 1993, 16 consecutive Chinese patients (mean age 50 years) with MOVC were retrospectively evaluated. The diagnosis in these MOVC patients was usually delayed with a meanlag time of lll months. Most of the cases were detected by a delicate ultrasonographic examination of the abdomen. Segmental narrowing of the inferior vena cava in 11 patients was the predominant type of MOVC, while five experienced a membranous obstructive type. Only one of five surgery-treated patients had a postoperation survival > 5 years, while five out of the nine patients who received conservative treatment still survived after a 6-15 year follow up. Two patients received percutaneous angioplasty (PTA). One survived 4 years and the other expired 5 years after the PTA. Two patients (12%) developed a hepatocellular carcinoma in their disease course, and the incidence was lower than in previous reports from Japan and South Africa. The incidence of hepatitis B surface antigen in MOVC did not increase in our patients compared with the general population. In conclusion, the inferior vena cava should be carefully evaluated in an ultrasonographic examination of the abdomen to increase the diagnosis rate of MOVC. Surgical intervention should be carefully justified according to the patient's symptoms and signs, the types of obstructive lesions and the expertise of the surgeons.     

TRA1 mRNA在肝硬化及肝癌组织中表达的研究

目的探讨肝癌(hepatocellular carcinoma,HCC)组织、肝硬化(liver cirrhosis,LC)组织及正常对照组织中肿瘤排斥抗原1(tumor rejection antigen 1,TRA1)mRNA的表达及关系。方法采用逆转录-聚合酶链反应的方法检测34例肝癌患者肝癌组织、癌旁肝硬化组织、非肝癌的肝硬化患者活检组织、肝血管瘤及肝内胆管结石等对照组织中TRA1 mRNA的表达,用捷达801分析软件对结果进行相对定量分析。结果肝癌组织、肝硬化组织、对照组织TRA1 mRNA表达率分别为95.00%、84.21%、50.00%,肝癌组与对照组间表达率的比较,差异有统计学意义(P0.05),肝硬化组织、对照组织表达率之间差异无明显统计学意义(P0.05);肝癌组织、肝硬化组织、对照组织TRA1 mRNA表达量分别为1.67±0.96、1.49±0.53、0.57±0.27;扩增产物表现出表达量的不同,呈现渐变趋势,肝癌组织、肝硬化组织与对照组之间差异有统计学意义(P0.05),肝癌组织与肝硬化组织比较,差异无统计学意义(P0.05)。结论 TRA1参与了肝硬化、肝癌的发生、发展,TRA1可能是肝硬化和肝癌潜在诊断标志物和治疗靶点。     

Liver stiffness as a predictor of hepatocellular carcinoma behavior in patients with hepatitis C related liver cirrhosis

Background: Risk strati cation and prognostication of hepatocellular carcinoma (HCC) help to improve patient outcome. Herein we investigated the role of liver stiffness measurement (LSM) in the prediction of HCC behavior. Methods: Totally 121 na ve patients with HCC were included. HCC radiological evaluation and staging were done. LSM was measured using virtual touch quanti cation. Patients were divided into early to intermediate HCC (BCLC-0, A and B) and late HCC (BCLCC and D). HCC was treated according to the BCLC stage. HCC recurrence-free interval was estimated. Results: The mean LSM inside the tumor was signi cantly lower than the peri-tumoral area and the cirrhotic non-cancerous liver parts (P<0.001). In late HCCs stage, the mean LSM inside the tumor and in the peri-tumoral tissue was lower than the corresponding values in the early to intermediate HCCs stage (P<0.001). LSM inside the tumor and in the peri-tumoral tissue negatively correlated with serum AFP, tumor vascular invasion, and stage (P<0.05). The recurrence-free interval was directly correlated to LSM inside the tumor and inversely to LSM in cirrhotic non tumorous liver part. Kaplan-Meier analysis showed that the recurrence-free interval was signi cantly longer in patients with LSM inside the tumor of ≥1.25m/s compared to those with LSM inside the tumor of<1.25m/s. Conclusions: LSM can serve as a potential non-invasive predictor for HCC clinical behavior and the recurrence-free interval following loco-regional treatments.     

Loss of heterozygosity of the retinoblastoma gene in liver cirrhosis accompanying hepatocellular carcinoma

Carcinogenesis is a multistep process. Most hepatocellular carcinoma (HCC) is preceded by liver cirrhosis, but the genetic changes involved in cirrhosis are not known well. The present study was conducted to evaluate aberration of the retinoblastoma (RB) gene in HCC and adjacent non-tumorous liver using 22 patients with chronic liver damage accompanying HCC. The specimens obtained by microdissection from paraffinembedded tissues were analyzed using an assay based on the polymerase chain reaction for highly polymorphic nucleotide sequences of microsatellites in theRB gene. Out of 22 cases, 15 showed constitutional heterozygosity for the microsatellite markers. In 11 (73.3%) of these 15 informative cases, the primary HCC foci showed loss of heterozygosity (LOH). In 8 of these 11 doubly informative (informative and LOH-positive in primary HCC) cases, LOH was found in 20 (64.5%) of 31 microdissected non-tumorous foci. All of the non-tumorous foci showingRB loss were cirrhotic lesions but there were no foci of chronic hepatitis. The remaining 4 cases without LOH in HCC foci showed no LOH in non-tumorous lesions. In our study, LOH of theRB gene was frequently observed in liver cirrhosis surrounding tumor.Abbreviations RB retinoblastoma - HCC hepatocellular carcinoma - LOH loss of heterozygosity - PCR polymerase chain reaction - (CA) _n cytosine-adenine - (AT) _n adenine-thymine - n number of repeats     

Prediction of chronic hepatitis B, liver cirrhosis and hepatocellular carcinoma by SELDI-based serum decision tree classification

PURPOSE: To screen potential serological biomarkers and develop decision tree classifications of chronic hepatitis B, liver cirrhosis (LC) and hepatocellular carcinoma (HCC), respectively, with high prediction score for improving diagnosis of liver diseases. METHODS: The total serum samples were randomly divided into three training sets (41 HBV and 35 health; 36 LC and 35 health; 39 HCC and 35 health) and three testing groups (34 HBV and 38 health; 18 LC and 52 health; 42 HCC and 47 health). Selected WCX2 protein chip capture followed by SELDI-TOF-MS analysis was applied to generate the serum protein profiles. Subsequently serum protein spectra were normalized and aligned by Ciphergen SELDI Software 3.1.1 with Biomarker Wizard including baseline subtraction, mass accuracy calibration, automatic peak detection. Once the intensities of selected significant peaks from the training data set were transferred to further BPS analysis, an optimized classification tree with sequence-decision was established to divide training data set into disease group and control group successfully. A double blind test was employed to determine the clinical sensitivity and clinical specificity of three models. RESULTS: After comparative analysis of SELDI based serum protein profile between the cases of disease and healthy, a HCC decision tree classification with sensitivity of 94.872% and specificity of 94.286%; a LC decision tree classification with sensitivity of 91.667% and specificity of 94.286% and a HBV decision tree classification with sensitivity of 95.122% and specificity of 94.286% were produced by BPS respectively. When three decision tree models were challenged by the double-blind test samples, clinical sensitivity and clinical specificity of these models were predicted in diagnosis of three liver diseases (HCC: 90.48 and 89.36%; cirrhosis: 100 and 86.5%; HBV: 85.29 and 84.21%). CONCLUSION: SELDI-based decision tree classifications showed great advantages over conventional serological biomarkers in the diagnosis of chronic hepatitis B, LC as well as HCC.     

Recurrence of hepatocellular carcinoma 102 months after successful eradication and removal of membranous obstruction of the inferior vena cava

We report a 54-year-old Japanese woman who developed liver tumors 102 months after hepatic resection for hepatocellular carcinoma (HCC) and percutaneous transluminal angioplasty (PTA) for membranous obstruction of the inferior vena cava (MOVC), which is one form of Budd-Chiari syndrome. In the present admission workup showed no evidence of co-infection with hepatitis B and C viruses. Dynamic computed tomography (CT) and magnetic resonance imaging showed an enhanced lesion, 1.5cm in diameter, in segment 3 of the liver, and no obstruction of the inferior vena cava after PTA. CT during both arterial portography and hepatic arteriography revealed another lesion, showing different hemodynamics, in segment 2. The patient therefore underwent hepatic resection, and the tumors were diagnosed histologically as HCC. The two tumors differed in their morphological features, one containing abundant fibrous stroma, whereas the other did not. The nontumorous liver tissue showed central zonal fibrosis, i.e., reversed lobulation, and partial expansion of nodule-like formations, indicating lack of progression since the situation seen at the initial hepatectomy. The presence of nontumorous liver tissue showing the above features suggests that, even after successful treatment for relief of congestion, patients who have had MOVC should be followed closely for as long as possible because of the risk of HCC recurrence. This is the first reported case of HCC recurrence after successful treatment of MOVC.     

Frequent loss in chromosome 8p loci in liver cirrhosis accompanying hepatocellular carcinoma

Most hepatocellular carcinoma (HCC) is preceded by liver cirrhosis, but the genetic changes involved in cirrhosis are not well understood. We therefore studied loss of heterozygosity (LOH) in cirrhotic and neoplastic foci in livers of 14 patients with HCC. The samples, microdissected from paraffin-embedded tissues, were analyzed using a polymerase-chain-reaction-based assay for dinucleotide repeat polymorphisms on 8p. Of the 14 cases, 13 showed constitutional heterozygosity for the microsatellite markers. In 7 (54%) of these 13 informative cases, LOH was detected in the primary HCC and, in these 7 doubly informative (informative and LOH-positive in primary HCC) cases, LOH was found in 16 (70%) of 23 liver cirrhotic foci. The pattern of 8p allelic loss was identical in each doubly informative tumor; however, some of the liver cirrhotic foci harbored an 8p loss identical to that seen in the primary HCC, some harbored a different 8p loss, and some did not harbor any 8p loss. The remaining 6 cases without LOH on 8p in HCC showed no 8p loss in any cirrhotic foci. Presumably HCC could develop from cirrhotic cells harboring 8p loss.Abbreviations HCC hepatocellular carcinoma - LOH loss of heterozygosity - PCR polymerase chain reaction - AH adenomatous hyperplasia - AAH atypical adenomatous hyperplasia     

Prostate-specific membrane antigen expression in hepatocellular carcinoma,cholangiocarcinoma, and liver cirrhosis

BACKGROUNDPrimary liver cancer includes three subtypes: Hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (CCA), and combined hepatocellular carcinoma. Patients with primary liver cancer experienced poor prognosis and high mortality, so early detection of liver cancer and improved management of metastases are both key strategies to reduce the death toll from liver cancer. Prostate-specific membrane antigen (PSMA) expression in the tumor-associated neovasculature of nonprostate malignancies including liver cancer has been reported recently, but conclusive evidence of PSMA expression based on the pathological type of liver cancer remains limited.AIMTo study the expression of PSMA in HCC, CCA, and liver cirrhosis.METHODSA total of 446 formalin-fixed paraffin-embedded (FFPE) liver tumor and liver cirrhosis tissue samples were obtained retrospectively from the Pathology Department of Tongji Hospital. Immunohistochemistry was used to detect PSMA expression in these 446 FFPE liver biopsy specimens (213 HCC, 203 CCA, and 30 liver cirrhosis). The tumor compartment and the associated neovascular endothelium were separately analyzed. PSMA expression was examined by two certified pathologists, and the final results were presented in a 4-point scoring system (0-3 points). Correlation between PSMA expression and clinicopathological information was also assessed.RESULTSPSMA was expressed primarily in the neovascular endothelium associated with tumors. The positive rate of PSMA staining in HCC was significantly higher than that in CCA (86.8% vs 79.3%; P = 0.001) but was only 6.6% in liver cirrhosis (P = 0.000). HCC cases had more 3-score PSMA staining than CCA had (89/213, 41.8% vs 35/203, 17.2%; P = 0.001). PSMA expression correlated positively with the stage and grade of HCC and CCA. In both liver cancer subtypes, there were more PSMA⁺ cases in stages III–V diseases than in stages I and II. High staining intensity of PSMA was more frequently observed in liver cancers at high grade and advanced stage. There was no significant association of PSMA expression with sex, age, region, α-fetoprotein, hepatitis B surface antigen, or tumor size in both tumor subtypes.CONCLUSIONNeovascular PSMA may be a promising marker to differentiate HCC from liver cirrhosis and a prognostic marker for anti-tumor angiogenesis therapy for HCC.     

Value of serum C-reactive protein measurement in the detection of hepatocellular carcinoma superimposed on liver cirrhosis

We investigated whether, in Italian patients, C-reactive protein (CRP) determination could be considered a useful adjunct, complementary to ₁-fetoprotein, in the detection of liver cancer. CRP was determined by particle-enhanced nephelometry in 171 subjects (102 male, 69 female). Fifty-five patients had mild chronic liver disease (CLD), 45 cirrhosis (CIR), 38 hepatocellular carcinoma (HCC); 33 subjects were healthy controls. Patients with HCC and CIR had higher CRP levels (P<0.05) than those found in patients with CLD and controls. CRP higher than 5 mg/l was found in 30/38 (78.9%) patients with HCC, 28/45 (62.2%) patients with CIR, 16/55 (29.1%) patients with CLD (² 56.0,P<0.0001). Sensitivity, specificity and diagnostic accuracy of CRP in diagnosing HCC with respect to CLD+CIR were: 78.9%, 56.0% and 34.9%. However, when considered only in the subgroup of patients with ₁-fetoprotein below or equalling 30 ng/ml, they were 50.0%, 54.3% and 4.3% respectively. In conclusion, CRP concentration is frequently elevated in patients with HCC, however, it does not seem to improve the ability of ₁-fetoprotein to discriminate HCC from CIR.     

A caval homograft for Budd-Chiari syndrome due to inferior vena cava obstruction

Transjugular intrahepatic portosystemic shunt (TIPS) is the standard treatment of Budd-Chiari syndrome (BCS) non responsive to medical therapy. However, patients with inferior vena cava (IVC) obstruction proximal to the atrium do not benefit from TIPS and a surgical approach is mandatory. We report the case of BCS due to intrapericardial IVC obstruction. We describe a novel surgical approach using a fresh caval homograft. An attempt to balloon dilatation of the IVC obstruction was complicated by right atrial disruption with tamponade and ventricular fibrillation. Lately, the patient successfully underwent a reconstruction of the cavo-atrial continuity by the interposition of a fresh caval homograft, a novel surgical approach never described before for BCS. Further follow-up revealed progressive reduction and resolution of ascites, and overall clinical improvement. IVC obstruction near to the atrium can be surgically approached with a new technique consisting in inferior vena cava resection and replacement with a caval homograft.     

Membranous obstruction of the inferior vena cava and its causal relation to hepatocellular carcinoma.

Although rare in most countries, membranous obstruction of the inferior vena cava (MOIVC) occurs more frequently in Nepal, South Africa, Japan, India, China, and Korea. The occlusive lesion always occurs at approximately the level of the diaphragm. It commonly takes the form of a membrane, but may be a fibrotic occlusion of variable length. Controversy exists as to whether MOIVC is a developmental abnormality or a result of organization of a thrombus in the hepatic portion of the inferior vena cava. The outstanding physical sign associated with MOIVC are large truncal collateral vessels with a cephalad flow. A dilated vena azygous is seen on chest radiography. Definitive diagnosis is made by contrast inferior vena cavography. The long-standing obstruction to hepatic venous flow causes severe centrolobular fibrosis and predisposes to the development of hepatocellular carcinoma (HCC). Percutaneous balloon angioplasty, transatrial membranotomy, or more complex vena caval and portal decompression surgery should be performed to prevent these complications. HCC occurs in more than 40% of South African Black and Japanese patients with MOIVC, but less often in other populations. It is thought to result from the tumour-promoting effect of continuous hepatocyte necrosis, although the associated environmental risk factors have not been identified.