Overview
Budd-Chiari syndrome (BCS), or hepatic venous/hepatic segmental inferior vena cava obstruction syndrome, is a low incidence global disease and the most common cause of extrahepatic portal hypertension.
The clinical signs of BCS were first described by Budd in his monograph “Diseases of the Liver” in the mid-19th century, and first described in detail from a pathological point of view by Chiari in 1899. Since then, similar clinical signs have been reported around the world, and more and more large cases of BCS have been recognized, especially with the improvement of modern imaging techniques such as interventional radiology, ultrasound and MRI.
The definition and scope of BCS has been controversial. Currently, BCS is broadly defined as a group of clinical syndromes in which obstruction of any nature occurs above the inferior hepatic lobular vein, below the entrance to the right atrium, and/or in the inferior vena cava of the hepatic segment, resulting in pathological changes in the liver such as sinusoidal stasis, hemorrhage, necrosis, and fibrosis, ultimately leading to post-sinusoidal portal hypertension.
Epidemiologically, the onset of BCS is independent of gender and can occur at any age, but half of them are concentrated in the age of 20-40. In addition to the regional high prevalence factor, 98% of patients come from economically backward rural areas, and the cause of BCS is unknown.
Regarding the etiology of BCS, so far, only 30%-40% of BCS can be diagnosed with a clear etiology, and the etiology of most cases is not well understood, but it is generally believed that it is related to congenital venous malformation and hypercoagulable state in the body. (1) Congenital vascular malformation: It is believed that the development and connection disorder of the embryonic hepatic vein and inferior vena cava germ is the cause of hepatic vein or inferior vena cava stenosis and occlusion. (2) Intravenous thrombosis: seen in hematologic diseases such as true erythrocytosis, paroxysmal sleep hemoglobinuria, antithrombin III deficiency, postpartum thrombotic thrombocytopenic purpura, and autoimmune diseases such as antiphospholipid syndrome, systemic lupus erythematosus, and also in malignancies, infections, pregnancy and oral contraceptives. The above-mentioned etiological states mostly have increased blood coagulation and are prone to thrombotic obstruction. The reason why the opening of hepatic vein is prone to thrombosis may be related to the fact that the connection between this section of inferior vena cava and hepatic vein is close to the right angle and prone to vortex flow and diaphragmatic movement during breathing and coughing, which may cause local endothelial damage to the inferior vena cava due to gravitational pulling of the liver. (3)Others:Extravascular compression causing obstruction of the hepatic venous outflow tract, mostly malignant tumors adjacent to the second hepatic hilar, rare ones such as cysts, hematomas, enlarged lymph nodes, amebiasis, herpetic encopresis, syphilitic granuloma, fibrous scar, hernia, etc. The obstruction of blood flow due to intravascular luminal bullae is mainly secondary to malignant tumors of the liver, kidney and adrenal glands, which form metastatic tumor emboli in the hepatic/inferior vena cava; primary cases are relatively rare and can be due to hepatic angiosarcoma, inferior vena cava or cardiac ear tumors.
Interventional treatment of Buhiga’s syndrome
Preoperative preparation for interventional therapy
(a) Patient preparation 1. psychological preparation. 2. improvement of auxiliary examinations. 3. control of ascites. 4. anti-infection. 5. correction of electrolyte disorders. 6. iodine allergy test. 7. skin preparation at the puncture site. 8. preoperative fasting. 9. preoperative anticoagulation therapy. 10. platelet supplementation.
(B) Physician preparation 1. Detailed medical history and positive signs. Comprehensively understand and grasp the results of all preoperative laboratory and imaging examinations. 2. Preoperative discussion. After the return of routine examination, intra-departmental discussion should be organized to jointly develop the interventional treatment plan, including the proposed opening of the vessel, puncture route, selection of balloon diameter, whether to place endovascular stent, possible complications during intervention, prevention and treatment of intraoperative complications, etc.
(C) Instrument preparation According to the results of the preoperative discussion, the relevant catheters, instruments and endovascular stents should be prepared in advance, and special instruments should be prepared for special cases.
(D) Drug preparation
(V) Room and other equipment preparation: The space of the catheterization room should be disinfected according to the aseptic requirements, and the technician should be responsible for the trial operation of the DSA machine, high-pressure syringe, image data recording system and ancillary equipment to ensure the normal operation of the equipment.
(vi) Signing the surgical protocol: As mentioned above, although interventional treatment is minimally invasive, serious complications such as pericardial tamponade, arrhythmia and abdominal hemorrhage may occur during and after the procedure, so the risks and possible complications of interventional treatment must be introduced to the family one day before the procedure, and their understanding must be obtained and they should sign the surgical protocol.
Inferior vena cava angioplasty
The ideal treatment for inferior vena cava obstruction is to recanalize the obstructed area and keep it open for a long time. Interventional treatment is used to open the occluded inferior vena cava directly in the lumen of the vessel, mainly using a balloon catheter to dilate it and, if necessary, placing a metal endoprosthesis to support the vessel to restore normal blood flow and keep it open for a long time to achieve a satisfactory treatment effect, which has the advantages of being less invasive and more effective than surgical treatment.
I. Interventional treatment of membranous obstruction of inferior vena cava
Interventional treatment of membranous obstruction of inferior vena cava is usually performed immediately after inferior vena cava angiography. According to the inferior vena cava angiogram, the site of the inferior vena cava septum, its morphology, course and the presence of small holes should be clarified first; the diameter of the inferior vena cava beneath the obstruction should be measured in order to select the size of the needle and balloon for rupture puncture; and then, the need for jugular puncture should be decided according to the morphology of the occlusion. It is advocated that transfemoral and transjugular venous puncture should be included as routine routes of puncture.
In addition to the guidewire, catheter, catheter sheath, and pressure measuring tube used for contrast examination, the following equipment should be prepared: ①exchangeable ultra-hard guidewire. ②10F to 12F dilatation catheter. ③ Balloon catheter (balloon length 4-8 cm, diameter 2.0-2.5 cm). ④Interatrial septal puncture needle: RUPS-100 puncture needle or homemade puncture needle for rupture of membranes.
2. Operation method
(1). If a small amount of contrast is seen on the contrast image in the form of a jet into the right atrium, it suggests the presence of a small hole in the central or lateral part of the membrane. Then, the soft tip of the guidewire is used to test for the orifice, and the guidewire and catheter can enter the right atrium and superior vena cava through the orifice. Afterwards, the superrigid guidewire is exchanged to feed a balloon catheter to the septum, and the septum is dilated by injecting 30% contrast into the capsule [this method is called percutaneous transluminal angioplasty (PTA)], usually three times in a row, to completely tear the septum. The contrast is reviewed after withdrawal of the balloon catheter.
(2). If there is no central hole in the inferior vena cava septum, that is, if the inferior vena cava is membranous obstruction, because some septa are unevenly thick and thin, there is a weak point, so when breaking the membrane, we must first use the hard tip of the guidewire to probe gently at multiple points under fluoroscopy, once the weak point is found, it is easy to break the membrane; if there is no weak point, the hard tip of the guidewire can be used to break the membrane by forcefully performing “central vertical”. If the inferior vena cava has a certain curvature, the angle of the front end of the puncture needle should be adjusted before breaking the membrane. After success, the balloon will be delivered to the lesion for dilation. If the stiff tip of the guidewire cannot pass through the septum, the membrane should be broken using an interatrial septal puncture needle or other puncture needles. In general, the atrial septal puncture needle is preferable to break the membrane from the bottom up because the distal curvature of the septum basically conforms to the proximal curvature of the inferior vena cava; the RPUS-100 puncture needle is preferable to break the membrane from the top down. When performing rupture, different puncture needles and routes should be used depending on the location, thickness, morphology, and course of the inferior vena cava septum. The size of the balloon catheter should be selected according to the diameter of the inferior vena cava below the septum as seen in the inferior vena cava angiogram, and the balloon diameter should be greater than 20% of the diameter of the inferior vena cava. If the obstruction is not completely relieved and the pressure drop in the inferior vena cava is not satisfactory, an internal stent should be placed after the balloon is dilated and reviewed by imaging. The thinner septum has better elasticity and the balloon is easy to dilate, but it is not easy to tear it completely. It is prone to restenosis and can be an indication for endoprosthesis placement; when the septum is thicker, restenosis is less likely to occur once it is torn.
II. Interventional treatment of segmental stenosis occlusion of the inferior vena cava
The interventional treatment of segmental stenosis occlusion of the inferior vena cava is basically similar to that of membranous occlusion of the inferior vena cava, except that the elastic retraction of segmental occlusion of the inferior vena cava is significantly greater than that of membranous occlusion after balloon dilation.
Operation method
1.Pre-positioned marked catheter: Percutaneously puncture the right internal jugular vein and deliver the 7F pigtail catheter into the right atrium at the entrance of the inferior vena cava so that the catheter tip is located in the inferior vena cava above the obstruction, and the catheter tip does not beat with the heart to indicate its correct position.
2.Breaking puncture: Through the right femoral vein, a single curved catheter is fed under the guidance of a guidewire to the lower end of the occlusion, and a puncture needle is fed through the catheter so that the needle is not exposed outside the catheter. The operator fixes the catheter with the left hand and rotates the puncture needle direction indicator handle with the right hand so that the puncture catheter is located in the middle of the inferior vena cava. The tip of the pigtail catheter placed above the occluded end is used as a marker, and if it is in a line under both frontal and lateral fluoroscopy, the puncture needle is advanced and a little contrast is injected every 0.5-1.0 cm into the needle, and the position of the needle tip is observed and whether it clearly penetrates outside the lumen of the vessel, and after there is a sense of breakthrough, if blood is drawn back from the puncture needle, 5 ml of contrast can be injected and contrast is seen entering the right atrium, indicating successful puncture.
If the membrane is broken through the femoral vein route, the membrane can be broken through the jugular vein route by downward puncture. At this time, the pigtail catheter is placed below the occluded end through the femoral vein route as a marker, and the guidewire is inserted downward into the femoral vein after the membrane is broken successfully, and then led out through the femoral vein sheath to make the guidewire penetrate the superior and inferior vena cava, and then balloon dilation or internal stent is placed through the femoral vein route to make the operation more convenient.
3.Balloon dilation: advance the puncture catheter, withdraw the puncture needle, and feed the lengthened ultra-hard guidewire into the superior vena cava. Pre-dilatation of the occluded segment using a 12F dilatation tube or endoprosthesis delivery device will help the balloon catheter enter the occluded segment in the next step, using a 20mm diameter balloon catheter to dilate segment by segment.
4.Contrast angiography and pressure measurement: The decision to place the endovascular stent is based on the results of angiography and pressure measurement
5.Endoprosthesis implantation: First, the stent delivery device is sent to the predetermined site, and the endoprosthesis is delivered into the delivery tube. When the front end of the stent reaches the front end of the delivery tube. Pause the pushing to verify and determine the position of the stent front end again. The right hand fixes the push rod, the left hand retracts the outer cuff, and the patient is instructed to hold his breath and release the stent. Finally, the angiography confirms that the endoprosthesis is properly positioned and the blood flow is unobstructed, and the operation is finished.
(iii) Precautions
(1) For those who have potential lumen, the soft tip of the guidewire can be used to explore. If the occluded end is short and there is a certain distance according to the right atrium, the hard tip of the guidewire can be used to puncture the membrane directly against the pigtail catheter, which is usually successful.
(2) For longer inferior vena cava occlusion or stiffer lesions, an atrial septal puncture needle must be used for successful puncture. For thrombus distal to the inferior vena cava occlusion, urokinase can be used first to dissolve the soft thrombus and then puncture. Experience has shown that the already mechanized thrombus does not fall off and the placed stent also plays a role in compression and fixation.
(3) The diameter of the internal stent should exceed 10%-15% of the dilated balloon, and the length should exceed 1-1.5 cm at each end of the lesion. If the lesion segment is long and two groups of internal stents are needed, there should be partial overlap between the two groups. The stent should be “Z”-shaped stent, whose mesh is larger to avoid obstruction and thrombosis of the hepatic or renal vein.
(4). Intraoperative and postoperative anticoagulants are given.
(5) Inner stents with denser mesh such as Wallstent should be used in the inferior vena cava, avoiding the opening of the main hepatic vein or the collateral hepatic vein and the renal vein when placing.
(6) For unsuccessful puncture, the following aspects should be considered: the puncture is not a true lumen; there may be congenital poor inferior vena cava union.
III. Application of endovascular stents in the inferior vena cava
(I) Indications
(1) Segmental stenosis or occlusion of the vena cava
(2) Inferior vena cava obstruction combined with thrombosis
(3) Restenosis after balloon dilation of inferior vena cava membranous obstruction
(4) Elastic retraction greater than 40% after balloon dilation of inferior vena cava membrane obstruction.
(2) Treatment of poor stent ejection
The following conditions may occur after release of the stent in the inferior vena cava.
(1) The diameter of stent ejection is less than 15mm, because the local peripheral pressure of inferior vena cava is greater than the stent elasticity, or because the stent elasticity is too small to overcome the local peripheral pressure of inferior vena cava.
(2) Interlocking between stent struts and failure to pop open.
(3) One end of the stent fails to pop open and is tapered.
All three cases are treated in the same way, and a balloon catheter can be used to dilate the stent with poor ejection.
(C) Double stenting of inferior vena cava and hepatic vein
The incidence of simultaneous occlusion of the inferior vena cava and hepatic vein is about 25% of BCS. Internal stents in the hepatic vein should be placed first, followed by internal stents in the inferior vena cava. It is technically difficult to place an inferior vena cava stent first and then place a hepatic vein stent through the inferior vena cava stent. It is worth noting that stents of 10 mm in diameter are prone to restenosis when placed in the hepatic vein, and stents of 14 mm or more in diameter are preferable.
IV. Complications of inferior vena cava angioplasty
1. Arrhythmia: The intraoperative guidewire and catheter enter the right atrium through the vena cava and cause arrhythmia. If necessary, lidocaine and isoptin can be given.
2, vascular rupture hemorrhage: inferior vena cava segmental occlusion, before intervention, we must perform inferior vena cava imaging of the upper and lower end of the occluded segment to understand the anatomical form of the inferior vena cava, the length of occlusion, collateral circulation, the main hepatic vein and the opening of the collateral hepatic vein, etc., so that we can have a good idea of the situation, and as a basis for determining the efficacy of the intervention. It is important to make sure that the puncture needle and the catheter marker at the proximal end of the occlusion are in a continuous line when puncturing, and that the front and side positions are consistent. Once the contrast agent is found to be deviated from the vessel or abnormally retained, the puncture should be stopped and the cause should be analyzed to prevent accidents.
3. Stent displacement: The stent can be displaced upward into the right atrium and downward to below the hepatic segment of the inferior vena cava. The common reasons for stent displacement are ① the diameter of stent is smaller than the diameter of inferior vena cava. (ii) The septum has a small range of binding to the diameter and the septum binding point is deviated from the center of the stent during membrane occlusion, which makes the stability of the stent poor. ③The patient’s breathing amplitude is larger when the stent is placed, which makes the body surface positioning deviate. The downward displacement of the stent may not be treated or replaced; the upward displacement of the stent may be dislodged into the right atrium, which is a more serious complication in the placement of the stent in the inferior vena cava and requires open-heart removal.
4. Stent restenosis or occlusion: restenosis or occlusion can occur after stent placement, and restenosis can occur in the stent lumen or below the stent. Stenosis in the stent lumen is mostly due to excessive endothelial proliferation, and occlusion is mostly due to simultaneous thrombosis.
5. Effect of inferior vena cava stent on hepatic vein: For BCS with a specific site of onset, whether it is a membranous occlusion of the inferior vena cava or a segmental stenosis or occlusion of the inferior vena cava, whenever an internal stent is placed in the inferior vena cava, it almost inevitably touches the opening of the hepatic vein. Interventional treatment of hepatic or parahepatic vein obstruction due to inferior vena cava stenting is more difficult.
Therefore, the development of a new stent that is suitable for the inferior vena cava and does not affect the blood flow to the hepatic vein opening is an important measure to improve the long-term efficacy of interventional treatment of BCS.
I. Postoperative treatment of interventional therapy
(1) Strictly restrict lower limb activities for 24 hours after surgery to prevent bleeding from the puncture site
(2) The amount of postoperative echo blood increases, so attention should be paid to the observation of respiration, heart rate and blood pressure changes, and appropriate restriction of activities to avoid the occurrence of heart failure.
(3) Appropriate application of antibiotics to prevent infection.
(4) Anticoagulation: Heparin 4000U/d intravenously, after 7 days, switch to aspirin 40mg 3 times daily and dipyridamole (Pansentin) 25mg 3 times daily for 3 months.
(5) Review the ultrasound 3 months after the operation to understand the postoperative recovery and vascular patency, and perform inferior vena cava angiography if necessary.
Treatment of restenosis after interventional therapy
(1) Causes of restenosis after interventional therapy
Restenosis after interventional therapy occurs mostly in the following cases
(1) Inadequate dilation of the stenotic segment or more adequate dilation but more obvious elastic retraction, mostly seen in membranous stenosis.
(2) Stenosis of the inferior vena cava or hepatic vein due to incomplete deployment of the internal stent.
(3) The stent does not completely cover the stented segment.
(4) Excessive repair and hyperplasia of the intima of the endoprosthesis.
(5) Postoperative anticoagulation is not standardized and thrombosis occurs.
(ii) Treatment principles
In case of stenosis due to membranous stenosis or occlusion, a larger diameter balloon (2.5 cm in diameter) can be applied for re-dilatation, which can usually resolve the stenosis. If the pressure drop in the inferior vena cava is not satisfactory after dilatation and the presence of stenosis is observed on imaging, an internal stent should be placed. If the stenosis is not completely covered by the endoprosthesis, another set of endoprosthesis can be placed, requiring an overlap between the endoprosthesis and the endoprosthesis. In case of restenosis caused by excessive intimal hyperplasia of the endoprosthesis, general balloon dilation can resolve the stenosis, and if small doses of intravascular radiotherapy are administered at the same time, restenosis can be prevented; in case of restenosis caused by thrombosis, anticoagulation and catheter thrombolysis are feasible, and balloon dilation therapy is given if necessary.
III. Development and prospect
The application of metal endoprosthesis greatly reduces restenosis or re-occlusion after PTA, and its morphological stability limits the retraction of the vessel, thus preventing unfavorable vascular remodeling, but the metal endoprosthesis itself is anticoagulant, and long-term anticoagulation therapy is required after placement. In contrast, restenosis after endoprosthesis is noted to be caused by intimal hyperplasia. At present, all types of stents have not completely solved the problem of restenosis and obstruction caused by fibroblast and smooth muscle cell proliferation and insufficient stent expansion force.
Hepatic vein angioplasty
I. Hepatic veinoplasty via femoral vein.
(a) Indications
(1) Hepatic vein opening with membranous perforation.
(2) Hepatic vein opening with membranous occlusion and weak septum.
(3) Inferior vena cava angiography shows a bulging septum.
(B) Contraindications
When both iliac veins are occluded
Operation method: Firstly, inferior vena cava angiography is performed through femoral vein puncture to determine the approximate location of the hepatic vein opening, then the membranous puncture is performed through the femoral vein route, and the Cobra catheter is used to search for the hepatic vein opening at the opening of the right hepatic vein, middle hepatic vein and left hepatic vein. The catheter will suddenly jump forward and enter the hepatic vein under fluoroscopy. If the force of the catheter cannot cut through the septum, then the membrane needs to be broken using a steel needle. When using a steel needle to break the septum, the front end of the needle should be more curved to effectively prevent injury to the right atrium and bleeding in the pericardial cavity caused by the needle slipping into the right atrium due to forceful puncture. After successful rupture, selective hepatic venography and hepatic vein pressure measurement are performed, followed by insertion of a dilatation tube and a balloon catheter.
Hepatic venoplasty via the femoral route is technically less difficult to perform because the procedure can be completed through only one route, and it is one of its advantages to be performed immediately after inferior vena cava angiography. However, in the patients with BCS intervention, there are not many cases where the transfemoral route is suitable for rupture and balloon dilation, and because of the acute angle between the inferior vena cava and the hepatic vein, the hepatic vein stent cannot be delivered and released, and if it is necessary to place an endovenous stent, it needs to be placed via the jugular route.
II. Hepatic vein angioplasty via jugular vein.
(a) Indications
(1) Membranous obstruction at the opening of the hepatic vein.
(2) Segmental obstruction at the opening of the hepatic vein.
(B) Contraindications
(1) Opening of the hepatic vein in the right atrium.
(2) The distance between the opening of the hepatic vein and the right atrium is less than 1 cm
(3) Presence of fresh thrombus in the distal trunk of the occluded hepatic vein.
(4) Coagulation dysfunction.
Operation method: Insert the pigtail catheter through the jugular vein or femoral vein to the lower end of the intrahepatic segment of the inferior vena cava, firstly perform inferior vena cava imaging to initially understand and judge the position of the opening of the right hepatic vein and the left hepatic vein, then insert the guiding catheter (Cobra catheter, RUPSS I100 puncture set, atrial septal puncture needle or straight tip catheter) into the intrahepatic segment of the inferior vena cava via the right jugular vein through the superior vena cava and the right atrium. The depth of the guide catheter into the inferior vena cava should be below the level of the opening of the hepatic vein, and the rupture puncture needle should be inserted via the guide catheter, and the rupture puncture needle should be retracted to the opening of the hepatic vein, and a trial puncture of the opening of the right or left hepatic vein should be performed under fluoroscopy. After successful rupture, selective hepatic venography is performed and hepatic vein pressure is measured, followed by insertion of a dilatation tube and balloon catheter. After balloon expansion, the pressure is measured again and the imaging is reviewed, and the decision to place an internal stent is made according to the pressure gradient.
Percutaneous transhepatic and transjugular venous hepatic venoplasty
(a) Indications
(1) Membranous or segmental occlusion at the opening of the hepatic vein, unsuccessful in breaking the membrane by transjugular venous puncture.
(2) Hepatic vein occlusion after placement of endovascular stent in the inferior vena cava.
(3) The opening of the hepatic vein is less than 1 cm from the lower edge of the right atrium.
(4) Hepatic vein with membranous obstruction with fine holes.
(II) Contraindications
(1) Those with large amount of ascites
(2) Coagulation disorders
(3) Extensive occlusion of the hepatic vein is a relative contraindication
(4) Hepatic vein occlusion combined with hepatocellular carcinoma, with the tumor located in the puncture channel
(4) Hepatic vein occlusion combined with hepatocellular carcinoma and tumor located in the puncture channel. The inferior vena cava is first punctured via the femoral route for inferior vena cava angiography and lateral compression, and the right jugular vein is punctured and a catheter sheath of 8F or more is placed in reserve. The hepatic vein can be punctured percutaneously via the liver in two ways. One way is to puncture the hepatic vein with a 21G Chiba needle under fluoroscopy between the seventh and eighth ribs in the mid-axillary line to understand the site and extent of hepatic vein obstruction and the condition of the traffic branches between the hepatic veins. After successful puncture, a 0.97 mm or 0.89 mm guidewire is inserted through the trocar needle, the distal end of the guidewire is inserted to the hepatic vein obstruction, the trocar needle is withdrawn, and a 4F or 5F Cobra catheter is inserted along the guidewire into the hepatic vein trunk for backup. In the second method, the thickest hepatic vein trunk or branch is directly punctured with an 18G puncture trocar under ultrasound guidance, and the guide wire is inserted via the trocar needle and the catheter is exchanged for insertion for hepatic venography and rupture. The selection of the puncture point should be based on three points. First, the direction of the puncture point should be as parallel as possible to the direction of the main trunk of the hepatic vein to facilitate the entry of the guidewire and catheter. Second, the distance between the skin puncture point and the hepatic vein should be as short as possible to reduce the tissue damage to the liver. Third, the distance between the hepatic vein puncture point and the hepatic vein occlusion should be as long as possible to facilitate the adjustment of the catheter and puncture needle and to avoid the catheter slipping out of the hepatic vein during guidewire exchange. The steps for percutaneous transhepatic paracentesis and transjugular hepatic venoplasty are as follows.
After percutaneous transhepatic insertion of the catheter into the main hepatic vein, hepatic venography is performed using a high-pressure syringe to further define the site, extent, degree and nature of hepatic vein obstruction. Hepatic vein pressure is measured after imaging. After successful dissection, the catheter is sent to the inferior vena cava and the soft tip of the guidewire is exchanged to enter the inferior vena cava. A vascular foreign body clamp is inserted through the jugular vein catheter sheath to the opening of the hepatic vein in the inferior vena cava to capture the soft tip of the guidewire already in the inferior vena cava, and the guidewire is pulled out of the hepatic vein through the venous catheter sheath, forming a percutaneous transhepatic guidewire trajectory into the hepatic vein, the inferior vena cava, the right atrium, the superior vena cava, and the jugular vein.
After the establishment of the guidewire trajectory, a 10F-12F dilating catheter is inserted into the jugular vein to pre-dilate the occluded segment, and then a balloon catheter is inserted to the occluded hepatic vein for dilation. After successful dilation, the balloon catheter is withdrawn and exchanged for the insertion of a contrast catheter, and venography and manometry are performed again to determine whether to place an endovenous stent in the hepatic vein according to the contrast and pressure gradient. The advantage of this method is that it has a high success rate in breaking the membrane and avoids blind puncture to break the membrane. Since only a 4-5F catheter is used to pass through the liver, the trauma to the liver from the catheter is minimized.
IV. Multi-route puncture method for hepatic vein dilation and endoprosthesis placement
In some difficult and complex cases, if single or double route puncture is not successful, percutaneous transhepatic puncture, trans-femoral vein and jugular vein multi-passage puncture should be used to achieve success. The sequence of multiple punctures is usually: the femoral vein is first punctured for inferior vena cava angiography, followed by the jugular vein, and finally percutaneous transhepatic puncture is performed. Among the multiple punctures, percutaneous transhepatic hepatic venography is the most meaningful for diagnosis and treatment.
(A) Indications for hepatic vein stent placement
(1) Acute restenosis after hepatic vein balloon dilatation: control angiography after hepatic vein balloon dilatation shows greater than 50% elastic retraction, and pressure drop in the hepatic vein is less than 10 cmH2O on pressure measurement.
(2) Restenosis after hepatic vein balloon dilatation: Satisfactory results during the first hepatic vein balloon dilatation, however, recurrence of clinical symptoms occurs after several months or years, and restenosis is confirmed by repeat imaging. There are two ways to treat restenosis: one way is to give balloon dilation and internal stenting of the restenosis; the second way is to find another hepatic vein to give balloon dilation and internal stenting.
(3) Segmental occlusion at the opening of the hepatic vein: if the segmental occlusion fails to achieve effective dilation after balloon dilation.
(4) Obstruction at the opening of the hepatic vein caused by the placement of an internal stent in the inferior vena cava.
(2) Contraindications to hepatic vein stent placement
(1) The opening of the hepatic vein is in the right atrium: the stent may be dislodged into the right atrium.
(2) The opening of the hepatic vein is less than 1 cm from the right atrium: there is also a risk of stent dislodgement into the right atrium.
(3) The hepatic vein and inferior vena cava are filled with fresh thrombus: the stent will be caught in the thrombus.
Procedure: Placement of intrahepatic stents is always performed immediately after balloon dilation and contrast angiography. Placement of hepatic vein stents is almost always via the jugular route, as this route keeps the stent delivery catheter largely straight and facilitates stent delivery. After withdrawal of the contrast catheter, the guidewire is retained, at which point a reinforced guidewire should be used and fed along the guidewire into the stent delivery device, which should be delivered deep into the hepatic vein. The stent should be delivered to the front of the delivery device under fluoroscopic surveillance, and the stent placement site should be determined according to the imaging image, and the adjacent bone or ruler should be used as a marker to slowly back off and adjust the delivery device to the marker, and the patient should be instructed to hold his breath, and the stent should be released while the patient is holding his breath. If the stent pops open satisfactorily, a contrast catheter should be sent to the distal end of the stent and the stent should be reconstructed and pressure measured; if the stent pops open unsatisfactorily, a balloon catheter should be used to expand the stent.
V. Hepatic vein angioplasty guided by the collateral hepatic vein.
(a) Indications
(1) Hepatic vein opening with membranous occlusion and small collateral hepatic vein, with traffic branch between collateral hepatic vein and hepatic vein.
(2) Hepatic vein occlusion with a large amount of ascites that cannot be performed by percutaneous transhepatic puncture.