CAVERNOUS TRANSFORMATION OF THE PORTAL VEIN (CTPV) is a chronic partial or complete obstruction of the portal vein in the hepatic portal or intrahepatic branches, resulting in obstruction of portal venous blood flow, causing increased portal venous pressure and, to reduce portal hypertension, the formation of collateral circulation around the portal vein or recanalization after obstruction. Patients may have recurrent vomiting of blood and tarry stools with mild to moderate splenomegaly and hypersplenism. Therefore, the liver function of such patients is good, so ascites, jaundice and hepatic encephalopathy rarely occur. Occasionally, cavernous degenerative collateral vessels may compress the common bile duct and cause obstructive jaundice.
CAVERNOUS TRANSFORMATION OF THE PORTAL VEIN (CTPV) is a chronic partial or complete obstruction of the portal vein in the hepatic portal or intrahepatic branches, resulting in obstruction of portal blood flow and increased portal pressure, and the formation of collateral circulation or obstruction around the portal vein to reduce portal hypertension. recanalization. This is a compensatory change of the body to ensure the amount of hepatic perfusion and normal liver function. It is a rare clinical condition and is one of the causes of prehepatic portal hypertension, accounting for about 3.5% of portal hypertension. The etiology is not fully understood. With the widespread use of DSA angiography, color US, MRI and CT, the number of reports has been increasing in recent years.
Symptoms and signs (view content) In the absence of portal hypertension, patients with primary CTPV may have no discomfort, and patients with secondary CTPV mainly have manifestations of the primary disease. After the development of portal hypertension, the main manifestations are portal hypertension and secondary rupture of esophagogastric fundic varices and/or concomitant portal hypertensive gastropathy. Patients may have recurrent vomiting of blood and tarry stools with mild to moderate splenomegaly and hypersplenism; therefore, the liver function of such patients is good, so ascites, jaundice and hepatic encephalopathy rarely occur. Occasionally, spongy degenerative collateral vessels may compress the common bile duct and cause obstructive jaundice.
Disease etiology (view content) Portal vein cavernous degeneration can be divided into primary and secondary depending on the etiology. CTPV in children is mostly primary, mainly due to the absence of the venous lumen of the hepatic portal and its branching divisions, structural congenital developmental abnormalities, stenosis or atresia. The following conditions are currently thought to cause CTPV in children.
1, congenital malformation of the portal vein, where an abnormal proliferation of the venous plexus between the umbilical mesenteric-hepatic vein occurs after venous duct occlusion to replace the occluded portal vein.
2, CTPV itself is a kind of angioma of the portal vein.
3, The outcome of portal vein thrombosis, sepsis in the newborn, umbilical infection and abdominal infection. Inflammatory lesions involve the portal venous system and eventually lead to portal vein occlusion and periportal collateral vein formation. In adults, portal vein spongiform changes are mostly secondary, characterized by the normal luminal structure of the portal venous system, but due to portal phlebitis, periportal fibrous tissue inflammation, thrombosis, coagulation disorders (erythrocytosis), tumor invasion, pancreatitis, etc., resulting in obstruction of portal venous blood flow, blood stagnation or increased blood flow, and increased pressure, and in order to relieve pressure, collateral circulation is established around the portal vein to recirculate. The widening of portal vein shows solid changes and fine tortuous vessels are seen around the portal vein. Most of the patients have been reported with cirrhosis and hepatocellular carcinoma. Xie Yinong reported 10 cases of portal vein cavernous degeneration, including 7 cases of cirrhosis, 2 cases of hepatocellular carcinoma, and 1 case of portal vein embolism after splenectomy. Other causes of embolism such as post splenectomy, long-term oral contraceptive use, umbilical vein cannulation, dehydration and hypovolemic shock can also lead to portal vein cavernous degeneration. However, despite a thorough history taking and a thorough examination, the cause of CTPV is still difficult to identify in 50-60% of cases.
The main pathophysiological changes of CTPV are the irregular arrangement of small proliferating veins in the portal vein, i.e., portal spongy sinusoidal changes, occlusion of the portal vein due to complete or partial thrombosis of the portal vein trunk or cancerous embolism, which leads to extrahepatic portal hypertension and the formation of a large number of collateral vascular clusters in the portal area or between the hilum. The collateral vessels of CTPV are derived from small veins and neovascularization associated with lymphatics, bile ducts, and blood vessels. As the lesions are located in the extrahepatic portal vein, the liver itself is often normal or very slightly diseased. There may also be varying degrees of abnormal liver function due to inadequate perfusion of the liver. When portal hypertension develops, one of the most significant pathological changes is the establishment of many traffic branches between the portal and body veins and their marked expansion, which increases blood flow and relieves portal pressure to some extent. When the portal vein obstruction is limited, such as in the case of main trunk obstruction, the collateral veins of the portal vein spongiosa can cross the obstruction site to connect with the open portal branches in the liver, allowing normal portal venous perfusion in the liver. In cases of extensive portal vein obstruction, inadequate compensation of the collateral veins can lead to portal hypertension despite the involvement of the collateral veins of the portal spongiosa in the portal circulation.
Diagnostic tests (view content) Diagnosis: In patients with recurrent upper gastrointestinal bleeding and mild or moderate splenomegaly with essentially normal liver function, the possibility of CTPV should be thought of. Confirmation of the diagnosis requires ultrasound or color Doppler examination combined with portal venography. Other auxiliary examinations.
1, abdominal ultrasound normal portal vein structure disappears, replaced by irregular curved vascular shadow, or honeycomb shape, in which blood flow is seen, the direction of blood flow is irregular; thickened vessel wall echogenic enhancement, visible intravascular thrombus. ueno based on color Doppler imaging performance of CTPV is divided into 3 types: type I shows normal portal vein structure is unclear, only shows portal vein area with honeycomb structure, primary CTPV is of this type; type II shows that the main trunk of portal vein can be shown, but the inner part is filled with embolic material and side branch veins can be seen around it; type III shows the presence of mass echogenicity near portal vein and the formation of side branch veins due to compression of portal vein. Type II and III are secondary CTPV manifestations.
2, abdominal CT The direction of blood flow is irregular, and intravascular thrombus can be seen.
(1)The structure of portal vein travel area is disturbed, the normal portal vein system structure disappears, the soft tissue mesh-like structure formed by entangled side branch veins is seen in the direction of portal vein travel, and the demarcation between them is unclear, after enhancement scan, the portal vein is obviously strengthened and interwoven into a network, sinusoidal or tubular soft tissue-like structure, and a thin strip-like hyperdensity shadow around the portal vein is seen in the portal part of the liver.
(2) Abnormal perfusion of the liver parenchyma. In the arterial phase, the contrast agent accumulates in the peripheral part of the liver parenchyma, forming a high-density band shadow, and sometimes a proximal dilated arterial shadow can be seen, while in the portal phase, the whole liver shows a uniform isointense shadow.
(3) In patients with portal hypertension, tortuous and dilated collateral circulation vessels can be seen in the coronary veins, paracord veins, retroperitoneal cavity, hepatogastroduodenal ligament and esophageal junction of gastric fundus, and in severe cases, the tortuous and clumpy shape.
3.Digital subtraction angiography (DSA) mainly shows that the normal portal vein structure in the portal vein travel area is not shown, and the normal portal vein is replaced by disproportionately tortuous, tumor-like dilated spongy vessels, showing a network of tortuous, dilated, serpentine veins parallel to the portal vein trunk, dilated splenic veins, gastric coronary veins and esophageal veins. veins and esophageal veins.
Upper gastrointestinal imaging reveals varices or irregular and nodular gastric folds in the esophagogastric fundus.
5.Gastroscopy may reveal varices in the esophagogastric fundus.
Differential diagnosis (view content) is to be distinguished from hepatic sclerosis portal hypertension and idiopathic portal hypertension in diagnosis.
Treatment options (view content) focus on treatment of portal hypertension and secondary ruptured esophagogastric fundic variceal bleeding and portal hypertensive gastropathy. Surgical treatment is the main treatment, and drug treatment only plays an auxiliary role.
1.Pharmacological treatment Application of drugs to reduce portal vein pressure, so that the resistance of portal vein system and its side branch circulation is reduced, visceral vasoconstriction, reduce the blood flow and pressure of portal vein and its side branch, so that the blood flow at the bleeding place is reduced to achieve the effect of hemostasis, and the rate of hemostasis is about 60%. The commonly used drugs are posterior pituitary hormone, 0.4μg/min intravenous drip. 14 peptide growth inhibitor, the first dose of 250μg intravenous push, followed by 250μg/h continuous intravenous drip. 8 peptide analog (octreotide), the first dose of 100μg intravenous push, followed by 250μg/h continuous intravenous drip.
2.Interventional radiotherapy Selective abdominal arteriography to determine the site and cause of bleeding, followed by catheter drug infusion or embolization treatment, can effectively control bleeding.
3.Endoscopic treatment Endoscopic injection of sclerosing agent into esophageal varices or ligation of esophageal varices and, if necessary, embolization of vessels by injection of tissue adhesive into the varices of the fundus to achieve hemostasis. The literature reports an efficiency of 80% to 96% and a rebleeding rate of 12% to 28%. However, this method can cause perforation and stenosis of the esophagus and occasionally thrombosis of other veins (splenic vein, superior mesenteric vein, etc.).
4.Surgical treatment is recommended for those with good liver function and hypersplenism.
(1) Bypass surgery; including superior mesenteric vein-inferior vena cava bypass, splenic vein-left renal vein bypass, distal splenic and renal vein bypass. Although shunts can reduce portal vein pressure and control gastrointestinal bleeding, excessive shunting of portal venous blood flow not only causes a decrease in blood flow to the liver, but also causes the occurrence of hepatic encephalopathy.
(2) Dissection: Various portal-chimeric venous dissection techniques have been widely used to treat prehepatic portal hypertension, but the efficacy is poorer than that of shunts. Since it is difficult to completely disconnect the varices, even the disconnected veins may “communicate” again under the effect of pressure difference; disconnection may also destroy the hepatic traffic veins, so it is seldom used as the preferred procedure. At present, there are commonly used dissection of the lower esophagus and perigastric fundus vessels, which can stop the hemorrhage and maintain the flow of portal vein to the liver.
(3) Shunt plus dissection: At present, most of them use combined shunt plus dissection. By relieving hypersplenism and reducing portal vein pressure, acute hemostasis and prevention of distant recurrent bleeding are achieved.
(4) Splenectomy: for splenomegaly and hypersplenism.
(5) Others: such as intra-portal vein balloon dilation dissection to control acute bleeding, intraoperative placement of abdominal catheter in splenic vein, postoperative placement of balloon dilation catheter for portal vein trunk dilation under radiological intervention via splenic vein catheter, which relieves portal vein obstruction and effectively reduces portal hypertension.
(6) Combination therapy: It has been clinically found that each procedure has disadvantages. Simple splenectomy can have a rebleeding rate of up to 90% and can cause fatal post-splenectomy sepsis, which should be avoided as much as possible. Splenectomy with flow dissection will further increase the portal vein pressure, and although it can play an immediate role in stopping acute bleeding, new collateral circulation will inevitably be established over time, and reoccurrence of bleeding is difficult to avoid. It has been reported in the literature that portal body shunt plus portal chiasis dissection is the best choice for the treatment of this disease. In particular, splenectomy + peripancreatic vascular dissection + fundoplication anastomosis of the lower esophagus (Phemister procedure) may result in better long-term hemostasis.
Complications (view content) are portal hypertension and secondary rupture of esophagogastric fundic varices and/or concomitant portal hypertensive gastropathy. Occasionally spongiotic degenerative collateral vessels may compress the common bile duct and cause obstructive jaundice.
Prognosis and prevention (view content) Prognosis: For prehepatic portal hypertension due to portal vein cavernous degeneration, a combined shunt with dissection (C-bridging of the superior mesenteric vein with the inferior vena cava) is preferred as long as the patient’s condition permits. In case of emergency, splenectomy with portal vein dissection to control bleeding should be followed by superior mesenteric vein and inferior vena cava C-bridge. For those who have already undergone dissection and are bleeding again, superior mesenteric vein and inferior vena cava C-bridging is added. It is important to note that bypass surgery is prone to embolism and should be considered carefully and preferably with autologous vessels. The bypass procedure should not be performed in patients after sclerotherapy. And sclerotherapy has many complications and limitations, so this method should not be the first choice, but can be used as a treatment for rebleeding after complete dissection.
Prevention: No information is available.
Epidemiology (view content) Balfour et al. first described portal vein spongiosis in 1869, and Klemperer proposed it as a congenital vascular malformation and a clinical rarity based on autopsy and pathological examination.Omakawa et al. successfully replicated an animal model of portal vein spongiosis by ligating the extrahepatic portal vein in rats.Triger Gaetano et al. defined the localized process of collateral circulation formation after portal vein thrombosis as portal vein spongiosis. These vessels were called “portal vein spongiform degeneration” because of their spongy angiomatous changes in the gross specimen view. It has been gradually recognized that portal vein spongiosis is a multiple origin lesion, with congenital factors accounting for 50% to 60% of the cases.