Overview: Budd-Chiari syndrome, also known as Budd-Giari syndrome, Pak-Chiari syndrome, and Bu-Chiari syndrome, is a syndrome of stasis portal hypertension or/and inferior vena cava hypertension caused by partial or complete obstruction of the hepatic veins or inferior vena cava of the hepatic segment due to various causes and impaired blood return. In Western countries, Buga syndrome is mainly characterized by hepatic venous obstruction, especially thrombosis. It is caused by a hypercoagulable state of the blood for various reasons or by long-term oral hormonal contraceptives, which cause endothelial inflammation of the hepatic veins and secondary thrombosis in the hepatic veins, blocking them. In Eastern countries, Buerga syndrome is mainly a mixed type with simultaneous obstruction of the inferior vena cava and hepatic vein, followed by the hepatic vein obstruction type, while the simple inferior vena cava obstruction type is the least common. Its etiology is unknown and needs further study. The disease is more common in young and middle-aged men, the ratio of men to women is about (1.2-2):1, and the age is 2.5 to 75 years, with 20-40 years being the most common. Etiology: Hepatic vein obstruction or inferior vena cava obstruction is mostly due to: ① thrombosis of hepatic veins due to hypercoagulable blood (caused by oral contraceptives, erythrocytosis); ② foreign compression of veins by tumors; ③ invasion of hepatic veins by cancer (e.g., hepatocellular carcinoma) or inferior vena cava (e.g., renal carcinoma, adrenal carcinoma); ④ congenital abnormal development of inferior vena cava (septum formation, stenosis, atresia). Previously, the literature reported that the majority of cases of hepatic vein thrombosis were reported in western countries such as the United Kingdom and the United States, while in China, India, and Japan, septal formation of the posterior segment of the hepatic inferior vena cava was more common. Studies have shown that diaphragm formation is indeed more common in inferior vena cava lesions, but it is often combined with hepatic vein obstruction, while simple inferior vena cava lesions are rare. The septum of the inferior vena cava in the posterior hepatic segment is generally very thin, 1 to 3 mm thick, in a relatively fixed position, mostly located 1 to 3 cm below the entrance to the inferior vena cava in the right atrium, corresponding to the plane of the 9 to 11 thoracic vertebrae. Most of them are located above the opening of the right hepatic vein, at the opening of the left and middle hepatic veins, or between the opening of the left and middle hepatic veins and the opening of the right hepatic vein, and a few are located below the opening of the hepatic veins. Clinical manifestations: 1.For simple hepatic vein obstruction, the symptoms of portal hypertension are mainly manifested as ascites, hepatosplenomegaly, esophagogastric fundic varices, upper gastrointestinal bleeding, etc. 2.In case of inferior vena cava obstruction, the symptoms of inferior vena cava are mainly manifested as varicose veins of both lower limbs, pigmentation, and even the formation of long-lasting ulcers. The lateral circulation is established, the superficial veins of the thoracic, abdominal wall and lumbar back are dilated and twisted, partially compensating for the return of the inferior vena cava, and its blood flow direction is upward as its characteristic. 3, late patients due to serious ascites, in order to alleviate the symptoms of repeated laparotomy to perform abdominal decompression, protein loss, coupled with low digestion and absorption, the formation of bone thin as wood, abdomen as large as a drum, and finally the patient often died of severe malnutrition, infection, ruptured esophageal varices bleeding or liver and kidney failure. Depending on how many vessels are involved, the degree of involvement and the nature and state of the obstructing lesion, it varies. It can be divided into acute, subacute and chronic types. Acute type: Mostly caused by complete obstruction of the hepatic veins, the obstructive lesions are mostly thrombosis. Most of them start at the opening of the hepatic vein, and the thrombus can spread rapidly to the whole hepatic vein. The onset of the disease is rapid, with sudden onset of epigastric distension, nausea, vomiting, abdominal distension, diarrhea, similar to fulminant hepatitis, progressive enlargement of the liver, pressure pain, mostly accompanied by jaundice, rapid growth of ascites, and pleural effusion, but the spleen is not enlarged. In fulminant cases, hepatic encephalopathy may develop rapidly, with progressive worsening of jaundice, oliguria or anuria, and may be complicated by diffuse intravascular coagulation (DIC), multiorgan failure (MOSF), spontaneous bacterial peritonitis, (SBF), etc. Most can die rapidly within days or weeks due to circulatory collapse (shock), hepatic failure, or gastrointestinal bleeding. Ascites, hepatomegaly and the rapid appearance of MOSF are the prominent manifestations of the disease. This type is more common in young women under 20 years of age in China. Subacute type: Mostly, the hepatic veins and inferior vena cava are involved simultaneously or successively. Intractable ascites, hepatomegaly and lower limb edema are mostly present simultaneously, followed by superficial varices of the abdominal wall, low back and chest, whose blood flow is directed upward, which is an important feature of Buga syndrome to distinguish it from other diseases. Jaundice and hepatosplenomegaly are seen in only 1/3 of patients and are mostly mild or moderate. In many cases, ascites formation is rapid and persistent, with elevated abdominal pressure and diaphragm elevation, and in severe cases, abdominal compartment syndrome (ACS) may develop, causing systemic physiological disturbances. If the abdominal pressure rises to 25 cmH2O and 50 cmH2O, oliguria and anuria will occur, respectively. Thoracic volume and pulmonary compliance decrease, cardiac output decreases, pulmonary vascular resistance increases, and hypoxemia and acidosis occur. Chronic type: The disease can last for more than several years, mostly in patients with septal obstruction, and is mild, but there are striking signs, such as thick, sinuous, angry veins in the chest and abdominal wall, pigmentation in the foot and shoe area, and chronic ulcers in some cases. Although there can be varying degrees of ascites, most tend to be relatively stable. Esophageal varices are often unnoticed by the patient and are only confirmed by endoscopy or radiography when sudden vomiting of blood, black stools or enlarged spleen is detected. Hepatomegaly is less pronounced in this type of patient than in subacute cases, with compensatory enlargement of the caudate lobe being the more characteristic manifestation, but the degree of sclerosis is increased, and the splenomegaly is mostly moderate, with the giant spleen rarely seen in intrahepatic portal hypertension. In advanced patients, the typical “spider man” physique may appear due to malnutrition, protein loss, increased ascites and emaciation. Hematological examination: In acute cases, polycythemia vera and increased hemoglobin may be present. In advanced cases of chronic type, if there is upper gastrointestinal bleeding or splenomegaly or hypersplenism, there may be anemia or thrombocytopenia or leukocytopenia. In acute cases, there may be increased serum bilirubin, increased ALT, AST and ALP, prolonged prothrombin time and decreased serum albumin, while in chronic cases, there are no significant changes in liver function tests. In chronic cases, there is no change in liver function tests. In ascites, if there is no spontaneous bacterial peritonitis, the protein concentration is often below 30 g/L and the cell count does not show an increase. Immunologic examination, serum IgA, lgM, IgG, IgE and C3 have no obvious characteristic changes. Ultrasound: Ultrasound of the abdomen can make the initial correct diagnosis in most cases, and the compliance rate can reach more than 95%. The site and length of hepatic vein and inferior vena cava obstruction can be detected at the top of the diaphragm and the second hepatic portal, as well as whether there is a combined thrombosis. Hepatomegaly and ascites are prominent findings in acute Buga syndrome. Doppler ultrasound has a high diagnostic value. Therefore, abdominal ultrasonography is the preferred, valuable and non-invasive examination for Buga syndrome. Hepatic vein, inferior vena cava, portal vein and arteriography: Angiography is the most valuable method to establish the diagnosis of Buga syndrome, and the following types of angiography are commonly used: (1) inferior vena cava angiography and manometry via the femoral vein route; (2) inferior vena cava angiography and manometry via the femoral vein route combined with the transjugular vein route; (3) hepatic vein angiography and manometry via skin-to-hepatic puncture. (4) Hepatic venography and manometry via the inferior vena cava route. Since the diagnostic accuracy of ultrasound, multilayer spiral CT and high-field MRI is basically the same as that of angiography, diagnostic imaging is basically no longer performed alone today. 4.CT scan: In the acute phase of Buga syndrome, CT scan shows diffuse hypodense enlargement of the liver with large amount of ascites, and the specific manifestation of CT scan is a highly recessional filling defect (60-70 Hu) in the posterior segment of the inferior vena cava and the main hepatic vein. Enhancement scans are important for the diagnosis of Buga syndrome. At 30s after contrast injection, speckled enhancement (central speckled area) was seen near the hepatic hilum, and the enhancement in the perihepatic region was not obvious, and there was extensive portal vein visualization, suggesting off-hepatic blood flow in the portal vein. The low-density band in the liver appears 60s after contrast injection with marginal enhancement or filling defect of the hepatic and inferior vena cava, which is highly suggestive of intraluminal thrombosis, and the marginal enhancement is due to the trophoblastic vessels in the vessel wall. MRI can show the low intensity signal of liver parenchyma in Buga syndrome, suggesting liver stasis and increased free water in tissues, and MRI can clearly show the open state of hepatic veins and inferior vena cava, even distinguishing fresh thrombus from mechanized thrombus or tumor thrombus. MRI can also show the arachnoid changes in the intrahepatic collateral circulation and the extrahepatic collateral circulation, so MRI can be used as one of the non-invasive examination methods for Buga syndrome. The venous blood from the caudal lobe of the liver returns directly from the short hepatic vein to the inferior vena cava. In the case of simple hepatic vein obstruction, the short hepatic vein is patent, and isotope scan examination shows sparse radioactivity in the hepatic region and dense radioactivity in the caudal lobe. Nuclear scan is not specific for the diagnosis of Buga syndrome, but only in some cases there is a relative increase in radioactive uptake in the caudate lobe, which has an important reference value in identifying cavernous hepatic hemangioma. 7. Endoscopy: Gastroscopy is not very helpful in the diagnosis of Buga syndrome. However, in chronic cases, especially for those who have had gastrointestinal bleeding, further understanding of the cause and site of bleeding can be obtained; in suspicious or difficult to identify cases, biopsy can be taken under direct vision to make a clearer diagnosis. Laparoscopic biopsy has the advantage of being safer and more reliable. 8.Liver puncture biopsy: In the acute stage of simple hepatic vein thrombosis, the central veins of liver lobules, hepatic sinusoids and lymphatic vessels are dilated, the hepatic sinusoids are depressed with blood, and the liver is diffusely hemorrhagic. Blood cells leak from the hepatic sinusoids into the perisinusoidal space and mix with the cells of the liver plate. There is hepatocyte necrosis around the central vein. At intervals, the hepatic plate cells are replaced by red blood cells. In late stages, the necrotic hepatocytes in the central region of the hepatic lobules are replaced by fibrous tissue, forming cirrhosis, and the rest of the hepatocytes regenerate, with dilated hepatic veins and sinuses. Diagnosis: Acute Buga syndrome is mostly characterized by right upper abdominal pain, massive ascites and hepatomegaly; chronic cases are mostly characterized by hepatomegaly, portal-somatic collateral circulation formation and persistent ascites. Non-invasive ultrasound, multilayer spiral CT and MRI scan can make the correct diagnosis of Buga syndrome in more than 95% of cases, but careful analysis of medical history and systematic physical examination should not be neglected. Treatment: 1. Interventional surgery Interventional treatment has become the treatment of choice for Buga syndrome because of its advantages of low trauma, good efficacy, high success rate, low recurrence rate and high repeatability. If the inferior vena cava or hepatic vein is combined with thrombosis, thrombolytic therapy can be inserted first, and balloon dilation therapy is feasible after complete dissolution of the thrombus to widen the narrowed section. If balloon dilation is not effective, stenting of the hepatic vein and inferior vena cava is possible. The specific surgical procedures are: (1) Inferior vena cava balloon dilation and angioplasty: the indications are septal type obstruction of the inferior vena cava, either stenosis or occlusion. (2) Inferior vena cava balloon dilation and stenting: for long segmental occlusions of the inferior vena cava. (3) Hepatic vein balloon dilation and angioplasty: Indications are for septal obstruction of the hepatic vein, whether stenosis or occlusion. (4) Hepatic vein balloon dilation and stenting: Indication is segmental occlusion of the hepatic vein. (5) Transjugular intrahepatic portosystemic shunt (TIPSS): Indications are extensive occlusion of the hepatic veins and severe cirrhosis. (6) Stirring thrombolysis and balloon dilatation-plasty of the inferior vena cava with fresh thrombosis: the indications are septal obstruction of the inferior vena cava with fresh thrombosis. (7) Inferior vena cava retrievable stent placement and balloon dilatation and angioplasty for combined old thrombosis: the indications are inferior vena cava obstruction combined with old formation. (8) Inferior vena cava preopening with balloon dilatation and angioplasty in combination with old thrombosis: the indications are inferior vena cava obstruction combined with old formation. Because of the complexity of the lesion types in Buga syndrome, which involves membranous obstruction of the inferior vena cava, membranous obstruction combined with thrombus of different nature, segmental obstruction, segmental obstruction combined with thrombus of different nature, membranous obstruction of the hepatic vein, membranous obstruction combined with thrombus of different nature, segmental obstruction, segmental obstruction combined with thrombus of different nature, and extensive occlusion of three hepatic veins, the interventional treatment should be selected according to the specific lesion Therefore, interventional treatment should be selected according to the specific lesions. Internal treatment includes low-salt diet, diuresis, nutritional support, and autologous ascites transfusion. For patients in the acute phase of thrombosis alone within 1 week of onset, anticoagulant therapy is available, but most cases are not diagnosed until weeks or months after thrombosis. In most cases, conservative treatment may buy time for collateral circulation to develop, but the patient will eventually require surgery. Patients with Buga syndrome, especially in advanced stages, often have intractable ascites and severe malnutrition. As a supportive therapy before surgery, medical treatment can improve the patient’s general condition, reduce surgical mortality, and facilitate the patient’s postoperative recovery. 3.Surgical treatment: (1)Direct vision diaphragmatic resection: the method is to enter the thoracic cavity through the right anterior 4th rib external thoracotomy or through the sternal incision, to cut the pericardium longitudinally in front of the right phrenic nerve, and to remove the obstructing septum. (2) Cavo-ventricular diversion: for limited obstruction or stenosis of the long posterior segment of the inferior vena cava, while the hepatic vein to the inferior vena cava is patent or there is a significantly enlarged right inferior major hepatic vein or other large lateral branches into the inferior vena cava; for failed rupture. This procedure should not be performed in cases of extensive obstruction or stenosis of the inferior vena cava or inflammation; it should not be performed in patients with complete obstruction of the hepatic veins or secondary cirrhosis or poor hepatic or renal function or poor peripheral condition; it is not easy to perform this procedure in cases of superior mesenteric vein obstruction. (3) Intestine-cavity and atrial diversion: when the patient’s portal hypertension and inferior vena cava hypertension are severe and the condition and anatomical conditions permit, the posterior wall of the intestine-cavity vein can be laterally anastomosed, while the anterior wall can be anastomosed with an artificial vessel, and then the other end can be anastomosed with the right atrium; also, on the basis of intestine-atrial or cavity atrial diversion, an artificial vessel of PTFE with an external support ring of 10 mm diameter can be made with the inferior vena cava or superior mesenteric vein. This procedure obviously increases the reflux. (4) Liver transplantation: In the advanced stage of the disease, the liver is severely sclerotic, liver function is near failure, various shunts and decompressions are not effective, and liver transplantation is the only salvage method.