Types Ⅰ, hepatic vein obstruction type: about 10% to 20%, hepatic venous pressure of 3.0-5.5kPa, hepatic venous return obstruction, hepatic stasis increased. (I summarize 25 cases of BCS: 12 cases of hepatic vein obstruction, accounting for 45% of the cases in this group are all from the area of Henan, Shandong and Jiangsu, which may be due to the different pathogenesis of the cases in the whole country and other countries in the world). Type Ⅰa, main hepatic vein obstruction, distal dilatation, accounting for more than 80%. Type Ⅰb, extensive stenosis or occlusion of the main hepatic vein, accounting for about 10%. Type II: inferior vena cava obstruction, accounting for about 50% to 70%. This type mainly consists of obstruction of the inferior vena cava of the hepatic segment, while more than one branch of the main hepatic vein is patent, or compensatory dilatation of the secondary hepatic vein and dilatation of the intrahepatic small veins, with the formation of collateral circulation. Type III: Obstruction of hepatic and inferior vena cava, accounting for about 20% to 30%. Type IV: small intrahepatic vein occlusion, rare. Interventional diagnosis and treatment techniques Angioplasty for Buchanan’s syndrome (BCS) is mainly inferior vena cava (IVC) angioplasty and hepatic vein (HV) angioplasty. Before opening the inferior vena cava and the hepatic vein, it must be remembered that: multi-location angiography should be performed to make sure that there is no thrombus before opening the blood vessels. If there is a thrombus with a large piece of thrombus, thrombolytic therapy should be placed in the tubes, and if the thrombus can’t be thawed out, the thrombus will be stent-inserted to cover and fix it to prevent acute large-scale pulmonary infarction. prevent acute massive pulmonary infarction. IVC plasty: 1, IVC membranous stenosis, occlusion of the catheter can first use the guidewire with the help of the catheter to see whether it can pass through the stenosis or occlusion section, if it can not pass through the membrane can be used to break the membrane with the curved end of the rupture needle pointing to the left anteriorly, through the stenosis, occlusion section, after the catheter is placed in the catheterization of imaging, to clarify the contrast agent is into the right atrium, and whether the leakage of the contrast agent abdominal cavity or pericardial visualization, if it is safe, then balloon dilatation of plasty or (( and) stent placement. and) stenting. 2.IVC segmental occlusion or longer occlusion should be broken by experience or feeling with rupture needle according to the above method, after passing through the narrow segment, end hole-multilateral hole catheter should be placed along the rupture needle for imaging, to make clear whether the contrast agent enters into the right atrium and whether there is any leakage of contrast agent into the peritoneal cavity or pericardial visualization, etc., and if it is safe, then balloon dilatation and molding or ( and ) stent placement can be performed. 3, the inferior vena cava occlusion longer can also be above, the inferior vena cava at the same time access catheter were placed in the occluded section of the proximal, distal, marking each other joint rupture of the membrane. HV plasty: In general, it is considered that the entire liver can satisfy the blood return as long as one main hepatic vein or secondary hepatic vein is patent. 1, Trans-IVC route HV plasty: The trans-IVC approach involves retrograde rupture of the stenotic or occluded segment of the HV with a rupture needle followed by balloon dilatation or (and) stenting. This approach is indicated only in a few cases of stenosis of the main hepatic vein or weak septum at the opening. Because of the small angle between the HV and IVC, the stiff tip of the guidewire or the rupture needle can not be delivered to the point of rupture, or the balloon can not pass along the guidewire through the stenotic segment after rupture of the membrane. 2.Transsuperior vena cava HV angioplasty: Balloon dilatation or (and) stenting after retrograde HV stenosis or occlusion via superior vena cava approach with a rupture needle. This route can increase the angle of guidewire passage and facilitate the balloon to follow through the stenotic segment, but it also has the disadvantage that if the patient has a combined IVC occlusion, the proximal end is shorter, and it is more difficult to support the rupture needle, which makes it more difficult to control the direction of rupture and penetration, and may even result in injury to the atrial wall due to the rebound of the needle tip. Above 1 and 2 in HV plasty for HV stenosis and septal weakness of patients with high success rate, but for septal thicker and and segmental occlusion of patients with low success rate, so there is a third method. 3, Percutaneous percutaneous hepatic perforation HV angioplasty: For patients who are unable to break the membranes via the superior and inferior vena cava, percutaneous percutaneous perforation HV access is required, and the guidewire is introduced into the dilated hepatic vein to break the membranes, and then the balloon is followed up with dilatation and angioplasty or (and) stent placement. This method is straightforward and has a high success rate, but it also has the disadvantage that all operations are done in the liver, which is more damaging to the liver (especially the balloon damage to the liver), and the puncture tract needs to be sealed with a gelatin sponge or a spring steel ring after the operation, so as to avoid more serious complications such as biliary fistulae or abdominal hemorrhage. 4, percutaneous HV combined with transjugular vein HV plasty: this method overcomes the shortcomings of the above methods (rupture of the membrane success rate is not high and the liver damage). Firstly, percutaneous HV ruptures the membrane in passing, and after success, the guidewire is placed into the superior vena cava, and then a catcher is placed into the jugular vein to lead out the guidewire, and the guidewire is replaced to strengthen the guidewire, and then balloon HV plasty or (and) stenting is followed up via the jugular vein. 5, HV plasty by marking method of paravalvular vein: when the hepatic vein is obstructed, there exists widely dilated collateral circulation in the liver, at this time, we can place the guidewire at the occlusion of the main hepatic vein as a marking through the narrowed paravalvular vein and collateral blood vessels, and then rupture the membrane of the jugular vein into the marking place in the liver. (Note: these side branches are thin and can not fully meet the liver blood return) 6, TIPSS: this method is suitable for patients with diffuse occlusion of the hepatic vein, and patients with re-occlusion after hepatic vein plasty and stenting. For patients with diffuse occlusion of intrahepatic veins, TIPSS can only solve the portal hypertension, and it cannot help to open the hepatic veins. With the advancement of technology and instruments, interventional therapy has the advantages of less trauma than surgical treatment, simple operation, fewer and lighter complications, and strong repeatability, etc. It has been popularized and popularized in the clinic, and some scholars in China have reported that more than 90% of BCS can be successfully treated by interventional therapy, which has replaced surgical treatment to a certain extent, and has become the first choice for the treatment of Buerger’s syndrome.