Budd-Chiari Syndrome: The Investigation Of Obstruction Membrane Position Of Inferior Vena Cava

Background and objectivesThe Budd-Chiari syndrome (BCS) is a heterogeneous group of disorders characterized by hepatiac venous outflow obstruction at the level of the hepatic veins (HV) and/or the inferior vena cava (IVC), which results in the congestion of portal hypertension (PHT) and/or inferior vena caval hypertension (IVCHT). BCS was considered as a rare disease in the past. With the development of imaging examination and the raise of clinical awareness to the BCS, more and more cases are reported, mainly situated in the middle and lower watershed of Huaihe River and Yellow River. BCS was often mistreated and misdiagnosed becasuse its non-specificity in sings, symptoms and clinical manifestation at early stage. The prognosis is poor and the five years survival rate is only around 10 percent if not be treated after symptoms appeared. With the progression, the patients'ability to work and quality of life are seriously affected.Because of diversity of the etiology,the pathology and clinical manifestations of BCS, it has become the emphasis,the research hotspots and difficulty in internal medicine, surgery, imaging and interventional radiology subjects. Although the long term efforts of scholars from different countries to research and explore BCS, with the development of interventional radiology, especially professor Han Xin-wei' breakthrough in the technology of big ballon dilation, blunt rupture of membrane, retrieval stent filter, stirring thrombolysis, and track technology, the diagnosis and treatment of BCS is made significant progress. BCS positioning diagnosis is a high degree of difficulty, with a high rate of early misdiagnosis and high recurrence rate of conservative treatment or symptom improvement after autologous compensatory high recurrence rate. All of those are closely related with the unclear causes and mechanism so that BCS could not be removed the causes.Therefore, it is necessary to carry out the overall painstaking research of BCS etiology.The causes of BCS are numerous, which are different with the geographic, ethnic, gender, age and pathological types. BCS is traditionally regarded as a blood disease resulting from defects in the blood anticoagulation system or aceentuation in the blood coagulation system with hypercoagulable state, this view has been widely accepted by scholars in China and abroad. In most Western countries that BCS is due to blood abnormal coagulation with high rate of thrombosis. But, the membrane obstruction of inferior vena cava gradually increases in recent years. In the East nation(especially in India and China), membrane obstruction of inferior vena cava accout for a important part, resulting mainly from coagulation, inflammation, infection, oral contraceptives, tumor or trauma can lead to BCS according reports in the literature, However, the etiology and pathogenesis of BCS are still unknown, so there are many problems that need urgent solution. The restenosis rate of surhepatic inferior vena cava after interventional radiolgy or operation for membrane obstruction in BCS is 20%. The main reason of long-term results for BCS is restenosis of IVC. Therefore, it is necessary to go on comprehensive and systematic reasearch for the etiology of BCS in China, which are of great significance at the clinical diagnosis and treatment and prevention of BCS in our country.With the department of medical imaging, more and more new examination techniques have been used in clinical diagnosis of the BCS. The commonly used methods to diagnose BCS are ultrasound(US),computed tomography(CT),magnetic resonance imaging(MRI) and digital subtraction angiography(DSA). According to domestic and foreign literatures, MSCT and MRI can be used for the diagnosis of BCS. After collecting original data, using most density projection method (MIP) volume restructuring method (VR) and many plane restructuring method (MPR) to vascular remodeling, CTA and MRA can easy to observation the obstructive membrane of IVC and adjacent structures.The purpose of this research is to explore the reasons of obstructive membrane of IVC by retrospectively analyze the obstruction membrane position of inferior vena cava and adjacent structures through medicine imaging, and to provide theoretical basis for choose the best broken membrane method in interventional radiolgy.Materials and method1. Clinical datasFrom January 2009 to February 2011 in The First Affiliated Hospital of Zhengzhou University for diagnosis BCS on the Picture Archiving and Communication Systems (PACS) involved in 306 cases, including May 2010 to August 2010 in Henan Province People Hospital by MRI for diagnosis BCS involved in 30 cases.171 cases of men,135 cases of women, aged 18 to 72 years old, average 41.16±10.88 years old, Its duration is 3 week to 28 years. Clinical manifestations include:fatigue, appetite weak, abdominal distension, ascites, hepatosplenomegaly, subcutaneous varicos vein of abdominal and thoracic wall, lower extremity edema, pigmentation, ulcers, hematemesis, irregular menstruation, infertility and so on.193 cases with BCS undergo interventional radiology. Choose 30 normal people as control group to examination MSCT from May 2010 to August 2010.2. Analyze and measure related data of the obstruction membrane of IVC and adjacent structures in BCS groupsThe obstructive lesions of IVC, the length of the lesions, the length of proximal part, the distance from the obstructive membrane of IVC to RHV,MHV,LHV,the Angle of RHV,MHV and LHV to IVC, the thickness of the obstructive membrane of IVC, the shape of the obstructive membrane of IVC, the distance from the obstructive membrane of IVC to the diaphragmatic top, the distribution of the obstructive lesion of hepatic vein and IVC in patients with BCS, those related data are analyzed and measured.3. Analyze and measure related data of IVC and HV in control groupsIncluding the angle of IVC in diaphragm section, the angle of RHV,MHV,LHV to IVC. The double blind method is applied to analyze and measure the image data by two experienced radiologists.The result which coincide with each other will be considered as the final result.The third radiologist will be asked to analyze and measure the unconfirmed result and to decide the final result. All the data are analyzed by SPSS 13.0 statistical package.Results1. The data of the obstruction membrane of inferior vena cava and adjacent structures in BCSOut of 306 patients there are 257 cases (84.0%)with vein obstruction both in HV and IVC. There are 181 cases (70.4%) with the membranous type of IVC in 257 patients with obstruction of IVC.The distance from RHV,MHV and LHV to the obstruction membrane of IVC is 4.40±2.08mm,3.21±1.39 mm,3.03±0.94mm, respectively. The mean thickness of obstruction membrane of IVC is 5.38±1.27mm. The distance from obstruction membrane of IVC to diaphragmatic top is 25.64±7.07. The obstruction membrane of IVC and diaphragm is parallel relationship; The shape of obstruction membrane of IVC:(not completely blocked is 17, vault type is 74, tapered type is 13, cant type is 41, plane type is 27, and the remaining iregular type is 9). The length and diameter of proximal part of obstruction membrane of IVC is 37.81±3.25mm and 18.45±2.51 mm, respectively. The angle of IVC is 159.04±1.81°.2. The related data of IVC and HV in control groupsThe angle of IVC is 157.39±3.18°in control groups. The angle of RHV,MHV and LHV to IVC is 70.42±12.31°,65.39±12.57°and 69.73±13.15°respectively.The data in control groups is different from that patiens in BCS.Conclusions1. The location of obstruction membrane of IVC is allmost lacated above the RHV2. Presume the causes of obstruction membrane of IVC is theory of chronic food poisoning and haemodynamics.3. The direction of IVC in diaphragm level is near to the ventral and to medial, the top of guide wire with 135-160°which as the angle of the IVC in diaphragm level. Puncturing occlusive membrance of IVC with blunt guide wire is safe, efficient, no serious complication and simple economic method.4. By coinciding the morphology of the obstructive membrance with suitable piercing direction can not only raise successful rate, but also can avoid and reduce the occurrence of severe complications.