Mesoportal bypass for extrahepatic portal vein obstruction in children: close to a cure for most!

Management of bleeding in extrahepatic portal venous obstruction

Extrahepatic portal venous obstruction, although rare in the western world, is a common cause of major and life threatening upper gastrointestinal bleeding among the poor in developing countries. Patients have large spleens and stunted growth. The diagnosis is easily confirmed by Doppler ultrasonography. Endoscopy sclerotherapy is the best option for the control of acute variceal bleeding. For secondary prophylaxis of bleeding, the choice lies between repeated sclerotherapy and a portosystemic shunt. We believe that due consideration should be given to performing a splenectomy and a lienorenal shunt. Performed by experienced surgeons, it carries a low operative mortality of 1%, a rebleeding rate of about 10%, removes the large spleen, reverses hypersplenism, and is not followed by portosystemic encephalopathy. Most importantly, it is a onetime procedure particularly suited to those who have little access to blood transfusion and sophisticated medical facilities.

Advantages of the meso-Rex bypass compared with portosystemic shunts in the management of extrahepatic portal vein obstruction in children

BACKGROUND

Consequences of extrahepatic portal vein obstruction (EHPVO) include variceal bleeding and hypersplenism due to portal hypertension, as well as metabolic abnormalities secondary to impaired portal venous circulation. The purpose of this study was to compare the effectiveness of meso-Rex bypass and portosystemic shunt (PSS) for reversing these symptoms in children with EHPVO.

STUDY DESIGN

All children with idiopathic EHPVO evaluated for potential meso-Rex bypass at a single institution between 1997 and 2010 were reviewed. Portosystemic shunt was performed in patients with refractory portal hypertension when meso-Rex bypass was not technically feasible. Outcomes of meso-Rex bypass and PSS were compared, including resolution of portal hypertensive bleeding and hypersplenism, as well as changes in liver synthetic function, ammonia levels, and somatic growth.

RESULTS

Sixty-five children with EHPVO underwent successful meso-Rex bypass, while 16 required PSS. Nearly all patients experienced complete relief of variceal bleeding after meso-Rex (96%) bypass and PSS (100%). The improvements in platelet count (+82.1 ± 60.0 vs +32.4 ± 56.3 thousand/μL; p=0.004), internal normalized ratio (-0.22 ± 0.27 vs 0.01 ± 0.14; p=0.022), and serum ammonia level (-26.8 ± 36.8 vs +19.4 ± 33.1 μM/L; p=0.002) were greater after meso-Rex bypass than PSS. Among patients with below average (standard deviation z-score<0) preoperative weight for age, the improvement in weight-for-age z-score was greater after meso-Rex bypass (+0.84 ± 0.98) than PSS (+0.17 ± 0.79, p=0.044). Median duration of follow-up was 4.45 years after meso-Rex bypass and 1.8 years after PSS.

CONCLUSIONS

Both meso-Rex bypass and PSS effectively relieve symptoms of portal hypertensive bleeding in children with EHPVO, although the meso-Rex better relieves hypersplenism. By restoring normal portal venous circulation, the meso-Rex bypass has additional metabolic benefits.

Percutaneous revascularization of reoccluded meso-Rex shunts in extrahepatic portal vein obstruction

Extrahepatic portal vein (PV) obstruction (EHPVO) is a rare disorder in early childhood with unknown incidence and mostly unknown etiology. In children with EHPVO, the hepatopedal flow of the mesenteric venous blood is hindered by an obstruction of the PV resulting in prehepatic portal hypertension. The curative treatment with a meso-Rex shunt connects the superior mesenteric vein to the left PV by a venous autograft. Despite good primary patency, reocclusion of a meso-Rex bypass and its treatment can be challenging. We present 2 patients with EHPVO with subtotal functional occlusion of a meso-Rex shunt treated by percutaneous interventions with short- and mid-term follow-up.

Meso-Rex shunt for immediate portal revascularization in pediatric liver transplantation: first report

We describe the case of a 13-month-old girl transplanted for biliary atresia with PV hypoplasia. She received the left liver lobe of her mother and presented intraoperative portal thrombosis. Because of technical reasons, the opportunity to have conventional PV reconstruction using the donor left PV stump was lost. Immediate conversion to a meso-Rex shunt, using the recipient jugular vein as a bridge between the superior mesenteric vein and the graft Rex recessus, allowed excellent portal revascularization of the transplant. We suggest that synchronous meso-Rex shunt may constitute a valid alternative to truncal PV anastomosis during pediatric LT.

Medical management of esophageal varices and portal hypertension in children

Portal hypertension (PH) is a common complication of chronic liver disease in children and represents a cause of morbidity and, rarely, mortality in this group of patients. Although often self-limiting, gastrointestinal bleeding in this setting is regarded as a frightening event by patients and carers, giving the impression of impending death. Therefore, it is important to raise the awareness on the natural history of PH in children, the utility of tools that help preventing and managing acute bleeding, and the signs predicting a poor outcome, thus indicating surgery. There is lack of data on the ability of endoscopy screening, endoscopic treatment of varices, and use of nonselective β-blockers to alter the outcome of PH in children; major efforts should be made to avoid such treatments empirically and promote multicenter trials instead. Nevertheless, such approach should be balanced against the need of offering the best care to children with PH. In this review, we discuss the advances made in the management of PH in children and compare it with the larger adult experience. A rational approach to acute gastrointestinal bleeding is proposed along with an algorithm suggesting a stepwise protocol to manage children with esophageal varices in the long-term, with some hints on possible future studies.

Surgical management of portal hypertension in children

The management of children with portal hypertension has dramatically changed during the past decade, with an improvement in outcome. This has been achieved by improved efficiency of endoscopic variceal control and the success of liver transplantation. Emergency surgical shunt procedures are rarely required, with acute bleeding episodes generally controlled endoscopically or, occasionally in adults, by interventional radiological procedures. Portosystemic shunts may be considered as a bridge to transplant in adults but are rarely used in this context in children. Nontransplant surgery or radiological interventions may still be indicated for noncirrhotic portal hypertension when the primary cause can be cured and to allow normalization of portal pressure before liver parenchyma is damaged by chronic secondary changes in some specific diseases. The meso-Rex bypass shunt is used widely but is limited to those with a favorable anatomy and can even be performed preemptively. Elective portosystemic shunt surgery is reserved for failure to respond to conservative management in the absence of alternative therapies.

Pre- and postoperative imaging of the Rex shunt in children: what radiologists should know

OBJECTIVE

The objective of this article is to illustrate the imaging features of patients with extrahepatic portal venous obstruction who are evaluated before or after a Rex shunt surgery.

CONCLUSION

The Rex shunt is a potentially curative surgical procedure that reestablishes physiologic hepatopetal portal flow. It is typically accomplished by interposing a vascular conduit between the superior mesenteric vein to the still patent intrahepatic portal venous system. This procedure results in resolution of portal hypertension.

Mesoportal bypass using a constructed saphenous vein graft for extrahepatic portal vein obstruction--technique, feasibility, and outcomes

BACKGROUND

The internal jugular vein is routinely used as a graft for the Rex shunt. We analyzed results of mesoportal bypass using an alternative autologous graft.

METHODS

Twenty-one children with extrahepatic portal vein obstruction were treated with a Rex shunt constructed using both greater saphenous veins. Follow-up included ultrasound and blood count screening at 3, 6, and 12 months and annually thereafter.

RESULTS

Median age was 8.7 years (range, 3.6-14 years), and follow-up time, 5.3 years (range, 0.6-7.1 years). Occlusion or narrowing occurred in 6 patients after a median of 20 months (range, 2.6-52 months). In 2 cases, patency was restored, giving an overall success rate of 81%. During follow-up, no variceal bleeding occurred while hemoglobin, platelet count, and leukocyte levels increased (P ≤ .02 for all) and spleen size decreased (P = .001). Patients with occlusive shunt complications weighed less (P = .01), had higher preoperative platelet levels (P = .02), and tended to have a smaller spleen preoperatively (P = .06) than patients without shunt complications. Cumulative graft patency at 6 months, 1 year, 3 years, and 5 years was 100%, 89%, 82%, and 74%, respectively.

CONCLUSIONS

Rex shunt constructed using the greater saphenous veins is a valuable alternative to the internal jugular vein graft, allowing long-term reversal of portal hypertension, splenomegaly, and hypersplenism. Low patient weight and high platelet count predicted shunt occlusion.

[Portosystemic shunt surgery between TIPS and liver transplantation]

Portosystemic shunt surgery in addition to transjugular intrahepatic portosystemic shunt (TIPS) insertion must still be regarded as a current treatment option for portomesenteric decompression in patients with pharmacological and endoscopic treatment failure, where liver transplantation is not imminent. This applies to secondary prophylaxis of rebleeding from varices in patients with well preserved liver function, e.g. liver cirrhosis CHILD A or extrahepatic portal vein thrombosis. Even if emergency endoscopy represents the treatment of choice in the acute bleeding situation, latest data from San Diego on emergency portacaval shunt surgery are encouraging. Likewise, portacaval shunt procedures can be an attractive alternative to TIPS or liver transplantation for acute Budd-Chiari syndrome or veno-occlusive disease.This article is an update on the systematics and methodology of portacaval shunt surgery, emphasizing the significance of this treatment option based on latest studies.

Adams-Oliver syndrome and portal hypertension: fortuitous association or common mechanism?

Adams-Oliver syndrome (AOS) is a rare condition defined by combination of cutis aplasia and transverse limb abnormalities. Some authors have described a possible association between this syndrome and portal hypertension (PH) due to hepatoportal sclerosis (HPS). We present a boy with AOS who developed a progressive splenomegaly and hypersplenism at the age of 2 months, and was admitted for acute gastrointestinal bleeding (GI) at the age of 9 months. Subsequently, we documented an extrahepatic portal vein obstruction and esophageal varices. After several episodes of cataclysmic upper GI bleeding a mesentero-portal shunt (MPS) was performed at 10 months. The shunt thrombosed, and after three failed attempts of thrombectomy, it was removed. One month later a splenorenal shunt was performed, and this closed spontaneously by 3 years. The patient suffered from ischemic stroke after placing the first shunt, and has spastic diplegia, left frontal lobe epilepsy, hyperactivity and attention deficit disorder, and severe psychomotor delay. At 11 years and he presented with chronic liver failure and hyperammonemia and coagulopathy. We hypothesize that there may be an early embryonic vascular abnormality (vascular disruption) that may explain these vascular phenomena.

Surgery for portal hypertension in children

Management of children with portal hypertension has evolved considerably over the past decades. Development of physiologic shunts (meso-Rex bypass) and successful liver transplant has changed the paradigm of portal hypertension surgery. Children with pre-hepatic portal hypertension are investigated and, if suitable, candidates are offered the mesenteric-to-left portal vein bypass (meso-Rex) preemptively, before development of symptoms of portal hypertension. Aggressive medical management, endoscopic ligation of bleeding varices, and radiologically placed intrahepatic stents have greatly reduced the need for emergent surgical procedures. A larger number of surgical options offer a permanent solution for children with portal hypertension in the setting of well-compensated liver function. Portal hypertension in the setting of decompensated liver disease is managed medically (via endoscopy) or radiologically (via transjugular intrahepatic portosystemic shunt) with the aim to offer liver transplant as a permanent solution.

Experience with duplex sonographic evaluation of meso-rex bypass in extrahepatic portal vein obstruction

Meso-Rex bypass is a surgical procedure for managing extrahepatic portal vein obstruction in children. Although duplex sonography has been used for assessing the patency of the bypass graft and the changes in the intrahepatic portal venous system after the surgery, there was little sonographic description of functioning and dysfunctioning bypass grafts found in the literature. In this case series, we retrospectively evaluated duplex sonography of functioning and dysfunctioning bypass grafts in 5 pediatric patients who received meso-Rex bypass grafts. Sonography was performed preoperatively and postoperatively within 48 hours, 1 to 2 weeks later, and at follow-up 1 month and up to 3 years later. Changes in the direction and velocity of the flow in the intrahepatic portal veins and bypass grafts and diameters of the grafts and the left portal veins were analyzed. Preoperative sonography revealed varied extension of extrahepatic portal vein occlusion with cavernous transformation and diminished intrahepatic portal venous flow, whereas postoperative studies showed a rapid increase of the intrahepatic portal flow via the meso-Rex bypass graft in all cases. A patent graft with reversed flow in the left portal vein was a predominant feature of a functioning graft. In contrast, absent flow in the graft with diminished flow or an altered flow direction in the left portal vein indicated graft failure. It is believed that duplex sonography provides a valuable tool for monitoring the hemodynamic changes in the portal venous system and detecting graft malfunction.