CTPV was first described by Balfour in 1869 and is a congenital or secondary lesion of the portal vein system in the anterior hepatic area that results in total or partial obstruction of the portal vein, resulting in compensatory formation of a large plexus of collateral vessels in the portal region of the liver, which appears spongy on imaging, hence the name.
In essence, it is a further pathological development of portal vein thrombosis (PVT) formation. The progressive course of the disease leads to a gradual increase in the pressure of the portal venous system, which eventually leads to a syndrome of portal hypertension characterized by esophagogastric varices or even ruptured bleeding and splenomegaly with splenomegaly, accounting for about 3.5% of all portal hypertension.
CTPV is a form of extrahepatic portal hypertension (EHPH) and is most common in children, accounting for about 40% of pediatric portal hypertension. 25%-40% of children have uncontrollable upper gastrointestinal bleeding.
Compared with adult cirrhotic portal hypertension, upper gastrointestinal bleeding in children with this disease is characterized by high risk, high rebleeding rate, and repeated bleeding. Therefore, the treatment of this disease has been the focus of research in hepatobiliary surgery and pediatric surgery at home and abroad. Now we would like to introduce the latest progress of surgical treatment of this disease, combining domestic and foreign literature and the author’s experience.
I. Etiology and typing of CTPV
1. Etiology: There is no clear explanation for the cause of CTPV. There are theories that the infection in the umbilical vein of children spreads to the portal vein, which leads to the formation of thrombotic obstruction in the portal venous system and eventually leads to the formation of CTPV in children. It has also been suggested that congenital malformations of the portal vein are the cause of CTPV in children. The causes of CTPV in adults are more complex.
Portal vein hemangiomas, portal vein carcinoma or septic thrombosis, hepatic venous obstructive disease, portal phlebitis, splenectomy, biliary perforation, liver abscess, perforated appendicitis, and cirrhosis of various causes may lead to portal vein inflammatory response or slowing of portal vein flow, which may lead to portal vein thrombosis and eventually to CTPV.
It has also been suggested that disturbances in coagulation mechanisms may also be a systemic factor in the formation of portal vein thrombosis and thus CTPV. It is certain that portal vein thrombosis is often the key pathological link in adult CTPV.
Type I: Extrahepatic, in which the main trunk of the portal vein is narrowed or absent, but the left and right branches of the intrahepatic portal vein are not involved. type II: Intra- and extrahepatic, in which the left and right branches of the intrahepatic portal vein are narrowed or occluded in combination with type I. type III: Intrahepatic, in which the left and/or right branches of the intrahepatic portal vein are diseased, but the extrahepatic portal vein trunk is not involved. The main trunk of the extrahepatic portal vein is not involved.
II. Palliative treatment of CTPV
The main clinical manifestation of CTPV is recurrent upper gastrointestinal bleeding due to portal hypertension, which is the main cause of upper gastrointestinal bleeding in children with portal hypertension. Therefore, the treatment of this disease focuses on how to control and prevent the ruptured esophageal variceal bleeding caused by it.
1. Pharmacological treatment: The rationale is based on reducing portal blood flow and portal resistance to blood flow, including vasopressin, growth inhibitors, adrenoceptor blockers and thrombolytic anticoagulation. It has been reported that p-blockers (propranolol) have the effect of slowing down heart rate and reducing portal pressure, which can reduce the 5-year risk of rebleeding in portal hypertension by 90%.
2. Endoscopic treatment: It includes endoscopic sclerotherapy and ligature treatment. Because of its satisfactory efficacy and the advantages of simplicity, minimally invasive, and wide applicability, it is the first-line means of preventive treatment for portal hypertension combined with upper gastrointestinal bleeding, along with drug treatment. It is also believed that endoscopic ligation combined with pharmacological treatment is more effective.
3. Surgical treatment: If endoscopic or pharmacological treatment fails, or if there is severe splenomegaly or hypersplenism, surgical treatment can be performed. The surgical methods include portal vein dissection, non-selective shunt and selective shunt, etc.
Portal portacaval dissection is a more purposeful procedure, directly blocking the paradoxical flow between the portal veins, thus providing definitive control of recent ruptured esophageal variceal bleeding. At the same time, portal hypertension and blood flow to the liver are maintained, which facilitates the maintenance of liver function.
However, this procedure treats the symptoms but not the root cause and has limitations, such as unresolved portal hypertension resulting in the formation of new collateral varices; higher probability of rebleeding (20%-50%); aggravation of portal hypertensive gastric disease; and aggravation of thrombosis in the portal venous system. Portal venous shunts are divided into non-selective and selective shunts. This procedure is technically mature and fundamentally reduces the portal vein pressure and subsequently the blood flow load in the esophagogastric varices, which can effectively prevent bleeding from variceal rupture M.
Among the selective shunts, the distal splenorenal shunt was once the procedure of choice for CTPV. However, because it reduces the normal flow from the portal vein to the liver, it has the disadvantages of impairing liver function, complicating hepatic encephalopathy, and preventing the normal development of the liver in children. With the maturation of endoscopic techniques and the use of Meso-Rex diversion, it is no longer the procedure of choice for the treatment of CTPV.
CTPV curative treatment methods
1.Liver transplantation: Liver transplantation can be used to treat both the symptoms and the root cause of CTPV with proven efficacy. Children with CTPV can choose parental liver transplantation or split liver transplantation. However, the procedure is complicated and technically difficult, and the adjuvant liver transplantation can lead to atrophy or even loss of transplanted liver due to portal vein steal syndrome. Coupled with the limitations of donor scarcity and high cost, liver transplantation cannot become the leading procedure for CTPV treatment.
2. Meso-Rex diversion procedure: This procedure has been widely recognized as a curative procedure for CTPV in recent years. This procedure aims to restore normal perfusion to the liver and reverse the consequences of portal hypertension and portal venous shunts by bridging the left branch of the portal vein or the open umbilical vein connected to it with the extrahepatic portal vein or other branches of the portal venous system through its own vascular graft.
This procedure was first proposed by deVilledeGoyet et al. in 1992 for the treatment of portal vein thrombosis after liver transplantation and later developed for the treatment of CTPV, which revolutionized the outcome of traditional palliative therapy for esophagogastric variceal bleeding and established a new strategy for the prophylactic treatment of esophagogastric variceal bleeding.
The Rex procedure can be performed only if the following prerequisites are met.
1. Jamieson type I or type II portal vein thrombosis;
2. No old thrombosis of the superior mesenteric vein or splenic vein of grade ID or higher;
3, structural integrity of the liver without irreversible pathological changes;
The vessels of the extrahepatic portal system commonly used in Rex surgery include: portal vein, superior mesenteric vein, inferior mesenteric vein, splenic vein and gastric coronary vein.
In classic Rex surgery, the usual autologous grafts are the internal jugular vein or external iliac vein. Therefore, preoperative Rex requires ultrasound, CT or MRI angiography to evaluate the vasculature of the portal system and, if necessary, preoperative or intraoperative portal venography.
The Rex procedure has the following advantages.
1. It conforms to the physiological situation and guarantees the portal blood flow in the liver, which is beneficial for improving liver function and for the liver and body development of children;
2, fundamentally solve the portal hypertension, prevent the rupture of esophageal vein bleeding brought about by this;
3.Reverse the splenic function;
4.Avoid the occurrence of hepatic encephalopathy caused by traditional shunt;
5.The possibility of anastomotic thrombosis is reduced, and the cost of treatment is lowered;
6, avoiding the portal vein spongy vascular area, making the operation simpler.
The difficulty of the Rex procedure is to dissect the left branch of the portal vein from the Rex fossa for the anastomosis. This procedure requires high surgical skill and vascular surgery technique, and not all CTPVs are suitable for this procedure due to the vascular condition, which also limits the application of this procedure.
Conclusion
The Meso-Rex diversion procedure is the treatment of choice for CTPV, which requires an individualized treatment plan that takes into account the patient’s physiology and pathological changes.
In cases where Rex surgery is not possible, liver transplantation may be considered. For ruptured esophageal vein bleeding, a distal splenorenal shunt may be an option to control and prevent rebleeding after failure of drug or endoscopic therapy or recurrent bleeding. Portal vein dissection may be used in cases where conservative treatment of acute bleeding has failed or as an alternative to bypass surgery. Along with more objective and reliable clinical evidence studies, CTPV will gradually achieve individualized evidence-based decision making and . Precision treatment model.