Direct bypassing of extrahepatic portal venous obstruction in children: a new technique for combined hepatic portal revascularization and treatment of extrahepatic portal hypertension

Effectiveness of anticoagulant therapy using heparin combined with Plavix after Rex shunt

Purpose

Rex shunt is an optimal surgery for the treatment of extra-hepatic portal venous obstruction (EHPVO) in children. Anticoagulant therapy has been used to keep the patency of the bypass vein in the Rex shunt. This study was to investigate the effectiveness of anticoagulant therapy using heparin combined with Plavix in improving the prognosis and shunt patency of Rex shunt.

Methods

From January 2010 to September 2019, 51 children with EHPVO underwent a portal cavernoma- Rex shunt. Based on whether using the anticoagulant therapy after the Rex shunt, all patients were divided into two groups: the anticoagulant group and the non-anticoagulant group. The diameter and flow velocity of the bypass vein were measured by the post-operative ultrasound, which was used to calculate the flow volume of the bypass vein (FV) and standard portal venous flow (SPVF). The bypass venous flow index (BVFI) was used to evaluate the ability of portal blood into the liver through the bypass vein after the Rex shunt, which was a ratio of FV to SPVF. The incidence of post-operative re-bleeding, the postoperative patency rate of the bypass vein, the remission rate of postoperative hypersplenism, the remission rate of postoperative esophagogastric varices and the BVFI were compared between the two groups.

Results

Of the 51 patients, 12 patients in the anticoagulant group were treated with heparin combined with Plavix after Rex shunt; 39 patients in the non-anticoagulant group were not treated with any anticoagulant therapy. 8 of 51 patients suffered from postoperative re-bleeding, of whom 6 patients with thrombosis of the bypass vein and 2 patients with anastomotic stenosis of the bypass vein. All 8 patients with re-bleeding belonged to the non-anticoagulant group. The remission rate of hypersplenism was no significant difference between the two groups after surgery (91% vs. 58%, P = 0.100). However, 3 patients without hypersplenism before surgery suffered from hypersplenism after surgery, who belonged to the non-anticoagulant group. There was no significant difference in the remission rate of esophagogastric varices (33% vs. 46%, P = 1.000). The BVFI of the anticoagulant group was significantly higher than that of the non-anticoagulant group (5.71 ± 5.89 vs. 1.1 ± 1.52, P = 0.003).

Conclusions

Anticoagulant therapy using heparin combined with Plavix plays an important role in maintaining the patency of the bypass vein, which improved the portal blood flow into the liver through the bypass vein after the Rex shunt.

Location and extent of cavernous transformation of the portal vein dictates different visceral side revascularization in Meso-Rex bypass

BACKGROUND

As an emerging standard of care for portal vein cavernous transformation (PVCT), Meso-Rex bypass (MRB) has been complicated and variated. The study aim was to propose a new classification of PVCT to guide MRB operations.

METHODS

Demographic data, the extent of extrahepatic PVCT, surgical methods for visceral side revascularization, intraoperative blood loss, operating time, changes in visceral venous pressure before and after MRB, postoperative complications and the condition of bypass vessels after MRB were extracted retrospectively from the medical records of 19 patients.

RESULTS

The median age of the patients (13 males and 6 females) was 32.5 years, while two patients were underage. Causes of PVCT can be summarized as follows: thrombophilia such as dysfunction of antithrombin III or proteins C; secondary to abdominal surgeries; secondary to abdominal infection or traumatic intestinal obstruction, and unknown causes. Intraoperatively, the median operation time was 9.5 h (7-13 h), and the intraoperative blood loss was 300 mL (100-1,600 mL). Ten cases used autologous blood vessels while 10 used allogeneic blood vessels. The vascular anastomosis was divided into the following types according to the site and approach: Type (T) 1-PV pedicel type, T2-confluence type, T3-major visceral vascular type; and T4-collateral visceral vascular type. Furthermore, the visceral venous pressure before and after MRB dropped significantly from 36 cmH2O (28-44) to 24.5 cmH2O (15-31) (P < 0.01). Postoperatively, one patient had delayed wound healing, two developed biochemical pancreatic fistulae, one experienced lymphatic leakage, the former caused by heat damage of the pancreatic tissues, the latter by cutting lymphatic vessels in the mesentery or removing the local lymph nodes during the process of separating the superior mesenteric vein, and one was re-operated on for an intervening intestinal fistulae. Postoperative enhanced CT scans revealed a significant improvement in abdominal varix in the patients with patent bypass, and at the 1-year postoperative follow-up, enhanced CT scans of six patients showed that the long axis of the spleen was reduced by ≥ 2 cm.

CONCLUSIONS

MRB can effectively reduce visceral venous pressure in patients with PVCT. It is feasible to determine the PVCT type according to the extent of involvement and to choose individualized visceral side revascularization performances.

Case report: Hepatectomy with Rex bypass for a child with hepatoblastoma and portal vein thrombosis

Pediatric liver tumors with portal vein obstruction are often candidates for liver transplantation. However, lifelong use of immunosuppressants and invasiveness to healthy donors in the case of living-donor liver transplantation is inevitable. Moreover, when lung metastasis is involved, the lung recurrence rate after liver transplantation is still high. Therefore, transplantation should be avoided as much as possible. In cases of tumors in the right lobe of the liver, complete resection of the portal vein trunk may be possible by creating a Rex bypass, but with the original method, end-to-side anastomosis to the umbilical portal vein is difficult in small children. We report a case of a 2-year-old girl with hepatoblastoma in whom a Rex shunt was created by end-to-end anastomosing the recanalized umbilical vein to the portal vein stump with interposing a vein graft, and the right lobe was successfully resected along with the tumor.

Surgical management of extrahepatic portal vein obstruction in children: advantages of MesoRex shunt compared with distal splenorenal shunt

PURPOSE

To review surgical management of extrahepatic portal vein obstruction (EHPVO) at Red Cross War Memorial Children's Hospital and compare MesoRex shunt (MRS) with distal splenorenal shunt (DSRS).

METHODS

This is a single-centre retrospective review documenting pre- and post-operative data in 21 children. Twenty-two shunts were performed, 15 MRS and 7 DSRS, over an 18-year period. Patients were followed up for a mean of 11 years (range 2-18). Data analysis included demographics, albumin, prothrombin time (PT), partial thromboplastin time (PTT), International normalised ratio (INR), fibrinogen, total bilirubin, liver enzymes and platelets before the operation and 2 years after shunt surgery.

RESULTS

One MRS thrombosed immediately post-surgery and the child was salvaged with DSRS. Variceal bleeding was controlled in both groups. Significant improvements were seen amongst MRS cohort in serum albumin, PT, PTT, and platelets and there was a mild improvement in serum fibrinogen. The DSRS cohort showed only a significant improvement in the platelet count. Neonatal umbilic vein catheterization (UVC) was a major risk for Rex vein obliteration.

CONCLUSION

In EHPVO, MRS is superior to DSRS and improves liver synthetic function. DSRS does control variceal bleeding but should only be considered when MRS is not technically feasible or as a salvage procedure when MRS fails.

REX SHUNT IN CHILDREN: COULD DYSFUNCTION BE PROGNOSED? A RETROSPECTIVE ANALYSIS

OBJECTIVE

The aim: To analyze retrospectively our experience of Rex shunt in children with symptomatic portal hypertension, its effect on hypersplenism regression and varices eradication, assess shunt survival and investigate risk factors, that could lead to shunt dysfunction and thrombosis.

PATIENTS AND METHODS

Materials and methods: 24 children (16 males, 8 females) ,with portal hypertension included into the study. All surgeries were performed within single center in a period from January 2010 to March 2022. Follow up period was 6.75±1.19 years.

RESULTS

Results: Age at diagnosis was 5.39±0.64 years. 5 (20.8%) had umbilical catheter in anamnesis. 16 (66.7%) manifested bleeding episodes as the first sign of portal hypertension. 9 (37.5%) of children manifested severe hypersplenism. Age at Rex shunting was 7.5±0.7 years. In 7 (31.8%) cases Rex shunt thrombosis occurred. 1 successful thrombectomy and 6 splenorenal shunting were performed. Kaplan-Meyer analysis showed Rex shunt survival 0.670 (95%CI 0.420-0.831). Logistic regression model indicated thrombocytes count (p=0.0423) and cytopenia (p=0.0272) as factors that could influence shunt thrombosis. Follow-up group included 18 patients. Spleen volume regression became significant by 1 p/o year p<0,05, thrombocytes significant increasement reached in 1 p/o months (p<0.01), varices involution was achieved by 1 p/o year (p<0,001).

CONCLUSION

Conclusions: Rex shunt effectiveness in study group was 70.9%., shunt survival assessed 0.670 (95%CI 0.420-0.831). Rex shunt was effective in bleeding prophylaxis in all patients of follow up group. Preoperative thrombocytes count (p=0.0423) and cytopenia (p=0.0272) were detected as factors that could influence shunt thrombosis, that is to be considered in RS preoperative period and require following studies.

The rex shunt for left portal vein reconstruction during hepatectomy for malignancy using of rex-shunt in adults for oncoliver surgery

BACKGROUND

Immediate portal reperfusion is mandatory following hepatectomy combined with portal vein (PV) resection. This retrospective study analyzes the feasibility and the outcomes of the Rex shunt (RS) for reconstruction of the left portal vein (LPV) and reperfusion of the remnant left liver or lobe following hepatectomy for cancer combined with resection of the PV in adult patients.

METHODS

From 2018 to 2021, an RS was used in the above setting to achieve R0 resection or when the standard LPV reconstruction failed or was deemed technically impossible.

RESULTS

There were 6 male and 5 female patients (median age, 58 years) with perihilar cancer (5 cases) or miscellaneous cancers invading the PV (6 cases). A major hepatectomy was performed in 10/11 patients. The RS was indicated to achieve R0 resection or for technical reasons in 8 and 3 cases, respectively, and was feasible in all consecutive attempts with (10 cases) or without an interposed synthetic graft (1 case). Two fatal complications (PV thrombosis and pulmonary embolism) and three non-severe complications occurred in four patients within 90 days of surgery. Two patients died of tumor recurrence with a patent RS at 13 and 29 months, and 7 were recurrence free with a patent shunt with a follow-up of 1 to 37 months (median, 15 months).

CONCLUSION

In case of remnant left liver or lobe following hepatectomy combined with resection of the PV, the RS may help to achieve R0 resection and is a valuable option to perform technically satisfying portal reperfusion of the remnant left liver or lobe.

Partial splenectomy in children undergoing liver transplantation or venous shunt for severe hypersplenism: A case control comparative study

BACKGROUND AND AIM

Hypersplenism is a consequence of portal hypertension and splenomegaly secondary to cirrhosis or portal cavernoma in children. In order to avoid persistent hypersplenism and splenomegaly after liver transplantation (LT) or venous shunt (VS), partial splenectomy (PS) may represent a relevant therapeutic option. The aim of this retrospective study was to evaluate the results of PS performed in children presenting hypersplenism.

METHODS

The following end-points were evaluated: (1) reversion of hypersplenism and its durability over time, (2) postoperative outcome, (3) courses of spleen size and volume and (4) comparison to a control group in which PS was not performed.

RESULTS

Between 1996 and 2020, 16 children underwent PS associated with LT (8 cases) for cirrhosis or VS (8 cases) for portal cavernoma. From Day 0 to 1 month, mean platelet and white blood cell counts (WBC) dramatically improved from 48 ± 19 at day 0 to 176 ± 70 × 10⁹/L (P < 0.0001) and from 2469 ± 853 to 7198 ± 3982/L (P = 0.001) respectively. PS allowed significant reduction of splenic length and volume from 176 ± 33 to 112 ± 24 cm (P < 0.0001) and from 1228 ± 464 to 450 ± 297 cm³ (P = 0.0003) respectively. After a mean follow-up of 92.6 ± 84.7 months (range: 4.1-210.7), 14 patients are alive with normal platelet and WBC counts and persistent spleen size reduction. Compared to control group, PS was associated with a significant platelet count rise from baseline to one year.

CONCLUSIONS

PS appears to be effective for treatment of hypersplenism and splenomegaly in combination with LT or VS without compromising outcome.

Optimal Treatment for Patients With Cavernous Transformation of the Portal Vein

Cavernous transformation of the portal vein (CTPV) is a sequela of extrahepatic and/or intrahepatic portal vein obstruction caused by a combination of local and risk factors. It was ever taken as a relatively rare disease due to its scant literature, which was mainly based on clinical series and case reports. CTPV often manifests as gastroesophageal variceal bleeding, splenomegaly, and portal biliopathy after the long-term insidious presentation. It is unable for CTPV to be recanalized with anticoagulation because it is a complete obstruction of the mesentericoportal axis. Endoscopic therapy is mainly used for temporary hemostasis in acute variceal bleeding. Meso-Rex shunting characterized by portal-flow-preserving shunts has been widely performed in children with CTPV. The multitude of complications associated with CTPV in adults can be effectively addressed by various interventional vascular therapies. With the ubiquity of radiological examinations, optimal treatment for patients with CTPV becomes important. Multivisceral transplantation, such as liver-small intestinal transplantation, may be lifesaving and should be considered for patients with diffuse mesenteric venous thrombosis.

Superior mesenteric vein to the right testicular vein shunt operation for jejunal varices bleeding associated with extrahepatic portal vein obstruction after pancreaticoduodenectomy: a case report

Background

Causes of extrahepatic portal vein obstruction include abdominal surgeries such as pancreaticoduodenectomy. We improved jejunal variceal bleeding due to extrahepatic portal vein occlusion after pancreaticoduodenectomy, by shunting of the testicular vein.

Case presentation

A 72-year-old man was diagnosed with extrahepatic bile duct cancer and underwent subtotal stomach-preserving pancreaticoduodenectomy 5 years ago. No postoperative complications occurred, adjuvant chemotherapy using gemcitabine hydrochloride was performed, and the patient remained recurrence-free. One year and 6 months post-operation, extrahepatic portal vein stenosis appeared, but no recurrence was noted. However, 4 years and 6 months later, recurrent gastrointestinal bleeding occurred, and the patient was diagnosed with an extrahepatic portal vein obstruction. Double-balloon enteroscopy showed capillary dilatation and varicose veins in the hepaticojejunostomy region, and venous bleeding from collateral blood vessels was diagnosed. A superior mesenteric vein to the right testicular vein shunt operation was performed, following which the gastrointestinal bleeding disappeared, and the anemia improved. Although transient hepatic encephalopathy occurred, conservative treatment relieved it. Double-balloon enteroscopy confirmed the disappearance of abnormal blood vessels.

Conclusions

A portosystemic shunt operation using the right testicular vein effectively relieved refractory variceal bleeding around the hepaticojejunostomy site in the jejunum due to an extrahepatic portal vein obstruction after pancreaticoduodenectomy.

Functional side-to-side splenorenal shunts to treat extrahepatic portal vein thrombosis in children

BACKGROUND

Surgical shunts are commonly used to manage complications resulting from extrahepatic portal vein thrombosis (EHPVT) in children. We describe a single-center experience utilizing a functional Side-to-Side Splenorenal Shunt (fSRS), created using either an enlarged inferior mesenteric vein (IMV) or left adrenal vein (LAV).

METHODS

Pediatric patients with isolated EHPVT who were poor candidates for a Rex shunt and who underwent a fSRS procedure at our institution between 2003 and 2020 were reviewed. The pre/post shunt portosystemic gradient change, rates of early and late complications, postoperative shunt patency, and mortality were evaluated.

RESULTS

Twelve EHPVT patients (mean age of 6.1 years) underwent a fSRS procedure. The mean portosystemic gradient change for the cohort was -11.7 mmHg (±4.9). There were no cases of recurrent variceal bleeding or episodes of shunt thrombosis reported after fSRS procedures.

CONCLUSIONS

Surgical shunts continue to be an important adjunct in the treatment of complications related to EHPVT. The functional Side-to-Side Splenorenal Shunt is a safe alternative that is easy to perform, involves minimal dissection and requires only a single anastomosis.

Meso-Rex bypass for the management of extrahepatic portal vein obstruction in adults (with video)

BACKGROUND

Extrahepatic portal vein obstruction (EHPVO) results in severe portal hypertension (PHT) leading to severely compromised quality of life. Often, pharmacological and endoscopic management is unable to solve this problem. Restoring hepatic portal flow using meso-Rex bypass (MRB) may solve it. This procedure, uncommon in adult patients, is considered the treatment of choice for EHPVO in children.

METHODS

From 1997 to 2018, 8 male and 6 female adults, with a median age of 51 years (range 22-66) underwent MRB procedure for EHPVO at the University Hospitals Saint-Luc in Brussels, Belgium. Symptoms of PHT were life altering in all but one patient and consisted of repetitive gastro-intestinal bleedings, sepsis due to portal biliopathy, and/or severe abdominal discomfort. The surgical technique consisted in interposition of a free venous graft or of a prosthetic graft between the superior mesenteric vein and the Rex recess of the left portal vein.

RESULTS

Median operative time was 500 min (range 300-730). Median follow-up duration was 22 months (range 2-169). One patient died due to hemorrhagic shock following percutaneous transluminal intervention for early graft thrombosis. Major morbidity, defined as Clavien-Dindo score ≥ III, was 35.7% (5/14). Shunt patency at last follow-up was 64.3% (9/14): 85.7% (6/7) of pure venous grafts and only 42.9% (3/7) of prosthetic graft. Symptom relief was achieved in 85.7% (12/14) who became asymptomatic after MRB.

CONCLUSIONS

Adult EHPVO represents a difficult clinical condition that leads to severely compromised quality of life and possible life-threatening complications. In such patients, MRB represents the only and last resort to restore physiological portal vein flow. Although successful in a majority of patients, this procedure is associated with major morbidity and mortality and should be done in tertiary centers experienced with vascular liver surgery to get the best results.

Meso-Rex bypass shunt vs. transposition shunt for cavernous transformation of portal vein in children

BACKGROUND

Cavernous transformation of the portal vein (CTPV) causes portal hypertension in children. Among Meso-Rex treatments, it is unclear whether the Meso-Rex bypass shunt (MRB) or the Meso-Rex transposition shunt (MRT) offers lower postoperative morbidity. Our objective was to evaluate postoperative outcomes, comparing MRB and MRT for children with CTPV.

METHODS

A retrospective study was conducted on children undergoing Meso-Rex for CTPV from January 2010 to December 2020. The primary outcome was shunt complications, including shunt stenosis and thrombus. The secondary outcome was re-operation.

RESULTS

Of the 43 patients included, 21 underwent MRT and 22 underwent MRB. MRT was associated with a higher rate of shunt complications when compared to MRB (23.8 vs. 9.1%, p = 0.191). The patients exhibited a higher rate of re-operation under the MRT than under the MRB (19 vs. 4.5%, p = 0.138). The operative time in the MRT group was significantly shorter than in the MRB group. Compared to MRT, the reduction in the length and thickness of the spleen was significantly greater in the MRB group. The increases in platelets were significantly higher in the MRB group than in the MRT group. The postoperative shunt velocity of MRB was notably faster than MRT. There was no significant difference in postoperative portal pressure between the two groups (p > 0.05).

CONCLUSION

Both MRB and MRT result in acceptable postoperative outcomes, but MRT is associated with higher post-shunt complications, which often increase the re-operation rate. This study suggests that MRB may offer advantages for children with CTPV.

Modified Meso-Rex bypass with umbilical vein recanalization and intra-operative stenting

PURPOSE

The aim of the study was to evaluate the usefulness of a novel modified Meso-Rex bypass surgical technique with umbilical vein recanalization and intra-operative stenting to treat portal vein cavernous transformation.

METHODS

In total, 13 portal vein cavernous transformation patients underwent Meso-Rex bypass surgery, consisting of bypass grafts between the superior mesenteric vein (SMV) and the recess of Rex as well as through the ligamentum teres hepatis without stent implantation (Group A, n = 9) and umbilical vein recanalization with intra-operative stent implantation (Group B, n = 4).

RESULTS

In Group A, the bypass diameter was 0-6 mm (median 3 mm) and blood flow velocity 25-115 cm/s (median 72 cm/s) 1 month after Meso-Rex bypass surgery, with open bypass times of 0-67 months (median 6 months); 6 patients in this group developed postoperative Meso-Rex bypass occlusions. A patient in Group A treated with ligamentum teres hepatis recanalization needed a thrombectomy and stent implantation during a second surgery 2 days after the Meso-Rex bypass, because of bypass thrombosis and umbilical vein stenosis. In Group B, the average modified Meso-Rex bypass diameter was 5.5-6.5 mm (median 6 mm), and the bypass vessels remained open in all patients, with blood flow rates of 45-100 cm/s (median 76.5 cm/s) 1 month after the modified Meso-Rex bypass, up to the endpoint (15-33 months, median 24 months). The rate of bypass occlusions in Group A and Group B were 22.2% and 0%, 30.0% and 0%, and 55.6% and 0% at 1 month, 3 months, and 1 year, respectively, after bypass surgery.

CONCLUSIONS

Our novel modified Meso-Rex bypass approach for portal vein cavernous transformation treatment was effective with excellent long-term bypass patency.

Value of preoperative computed tomography for meso-Rex bypass in children with extrahepatic portal vein obstruction

Background

Extrahepatic portal vein obstruction (EHPVO) is the most important cause of hematemesis in children. Intrahepatic left portal vein and superior mesenteric vein anastomosis, also known as meso-Rex bypass (MRB), is becoming the gold standard treatment for EHPVO. We analyzed the value of preoperative computed tomography (CT) in determining whether MRB is feasible in children with EHPVO.

Results

We retrieved data on 76 children with EHPVO (50 male, 26 female; median age, 5.9 years) who underwent MRB (n = 68) or the Warren procedure (n = 8) from 2013 to 2019 and retrospectively analyzed their clinical and CT characteristics. The Rex recess was categorized into four subtypes (types 1–4) depending on its diameter in CT images. Of all 76 children, 7.9% had a history of umbilical catheterization and 1.3% had leukemia. Sixteen patients (20 lesions) had associated malformations. A total of 72.4% of Rex recesses could be measured by CT, and their mean diameter was 3.5 ± 1.8 mm (range 0.6–10.5 mm). A type 1, 2, 3, and 4 Rex recess was present in 9.2%, 53.9%, 11.8%, and 25.0% of patients, respectively. MRB could be performed in patients with types 1, 2, and 3, but those with type 4 required further evaluation. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of CT were 100%, 83.8%, 42.1%, 100%, and 85.5%, respectively.

Conclusions

Among the four types of Rex recesses on CT angiography, types 1–3 allow for the performance of MRB.

Surgical shunts for extrahepatic portal vein obstruction in pediatric patients: a systematic review

BACKGROUND

Extrahepatic portal vein obstruction (EHPVO) causes portal hypertension in noncirrhotic children. Among surgical treatments, it is unclear whether the meso-Rex shunt (MRS) or portosystemic shunt (PSS) offers lower post-operative morbidity and superior patency over time. Our objective was to evaluate long-term outcomes comparing MRS and PSS for pediatric patients with EHPVO.

METHODS

A systematic review was conducted of articles reporting children undergoing surgical shunts for EHPVO from 1/2000-2/2020. Of 87 articles screened, 22 were eligible for inclusion. The primary outcome was shunt thrombosis and secondary outcomes included non-operative complications, stenosis, and re-operation.

RESULTS

Eighteen of 22 studies were of good quality and four had fair quality. Of 461 patients included, 340 underwent MRS and 121 underwent PSS. MRS were associated with a higher rate of post-operative thrombosis when compared to PSS (14.1% vs 5.8%, p = 0.021). There were 40/340 MRS patients (11.8%) that required at least one re-operation for either shunt thrombosis or stenosis, versus 5/121 PSS patients (4.1%), p = 0.019.

CONCLUSION

Both MRS and PSS result in acceptable long-term patency rates, but the more technically demanding MRS is associated with higher post-shunt thrombosis, often requiring further operative intervention. This study suggests that PSS may offer advantages for pediatric patients with EHPVO.

Standard or Variant Meso-Rex Shunts for Children with Variceal Bleeding due to Extrahepatic Portal Vein Obstruction: A Report of Two Cases

Extrahepatic portal vein obstruction (EHPVO) is the most common cause of pediatric portal hypertension and can cause life-threatening variceal bleeding. Meso-Rex shunt (MRS) is a surgical procedure that restores physiological portal venous blood flow to the liver by using a graft to connect the superior mesenteric vein and the left portal vein within the Rex recess, and can relieve variceal bleeding and other complications associated with EHPVO. Although the MRS is regarded as an optimal and potentially curative treatment with good long-term patency, graft thrombosis or failure due to unknown causes is not rare, prompting the need for further research on the risk factors of graft failure or poor patency. Herein, we report two cases of EHPVO in patients with recurrent or uncontrolled variceal bleeding, one treated with the classic Rex shunt and the other with the modified Rex shunt, which resulted in a failure and success, respectively.

Cirrhosis and Bleeding Esophageal Varices: Historic Perspectives

The paper describes the fundamental discoveries in the definition and treatment of patients with bleeding esophageal varices and cirrhosis.

The role of surgical shunts in the treatment of pediatric portal hypertension

BACKGROUND

Portal diversion by surgical shunt plays a major role in the treatment of medically refractory portal hypertension. We evaluate our center's experience with surgical shunts for the treatment of pediatric portal hypertension.

METHODS

All patients who underwent surgical shunt at a single institution from 2008 to 2017 were reviewed. The primary outcome was intervention-free shunt patency.

RESULTS

In this study, 34 pediatric patients underwent portal shunt creation. The median age was 7.7 years (interquartile range 4.3-12.0). Twenty-nine patients (85%) had prehepatic portal hypertension and 5 patients (15%) had intrahepatic portal hypertension. The primary manifestations of portal hypertension were esophageal varices (97%) and gastrointestinal bleeding (77%). Eighteen patients (53%) underwent meso-Rex bypass, 10 patients (29%) underwent splenorenal shunt, and 6 patients (18%) underwent mesocaval shunt. Outcomes were notable for minimal wound complications (9%), rebleeding events (12%), and mortality (3%). In the postoperative setting, 10 patients (29%) experienced a shunt complication (occlusion or stenosis), 4 of which occurred in the early postoperative period and required urgent intervention. The 1-year and 5-year "primary patency" patency rates were 71% and 66%, respectively.

CONCLUSION

Children suffer significant morbidity from the sequelae of portal hypertension. Our experience reinforces the feasibility of surgical shunts as an effective treatment option associated with low rates of morbidity and mortality.

Multimodality imaging of the Meso-Rex bypass

Extrahepatic portal vein obstruction (EHPVO) is the most common cause of upper gastrointestinal bleeding in children. It is defined as thrombosis of the extrahepatic portal vein with or without extension to the intrahepatic portal veins. The Meso-Rex shunt is the gold standard treatment in children with favorable anatomy since it restores physiological portal liver reperfusion. This is achieved by rerouting the splanchnic venous blood through an autologous graft from the superior mesenteric vein (SMV) into the Rex recess of the left portal vein, curing portal hypertension by doing so. General and hepatobiliary radiologists must be familiar with multimodality imaging appearances of EHPVO and with the role of imaging in identifying suitable candidates for Meso-Rex bypass surgery. Imaging might also detect complications of this procedure, some of which might be treated via interventional radiology.

Recanalization of Chronic Extrahepatic Portal Vein Obstruction in Pediatric Patients Using a Minilaparotomy Approach

PURPOSE

Extrahepatic portal vein obstruction (EHPVO) is the most frequent cause of portal hypertension in children. Some patients are not amenable to meso-Rex bypass and alternative surgeries do not restore physiologic flow. We aim to demonstrate the feasibility and safety of minilaparotomy for recanalization of chronic EHPVO.

METHODS

This 2013-2015 single-center, retrospective review included pediatric patients with chronic EHPVO who underwent minilaparotomy, mesenteric vein access, and attempted recanalization of the occluded portal vein. Outcomes included portal patency, resolution of variceal bleeding, size and number of varices, spleen size, and platelet count.

RESULTS

There were 6 EHPVO patients. The median age was 9.9 years and median duration of EHPVO was 7 years (3-16 years). EHPVO etiologies were liver transplantation (50%), idiopathic (33%), and umbilical vein catheterization (17%). Four patients (67%) had successful portal vein recanalization and stenting. At last follow-up [median 3.1 years (2.2-4.3 years)] all successfully recanalized patients had patent portal vein stents and resolution of varices and variceal bleeding. The median reduction in spleen size was 26%, with improvement in platelet counts (50-310/μL). The 2 patients with an idiopathic etiology may have never had a main extrahepatic portal vein based on imaging, and both were unable to be recanalized.

CONCLUSIONS

Recanalization and stenting of a prolonged occlusion of the portal vein via a minilaparotomy approach is feasible, safe, and may provide an alternative to shunt surgery or endoscopic therapy in selected patients.

MR angiography and 2-D phase-contrast imaging for evaluation of meso-rex bypass function

BACKGROUND

The meso-Rex bypass restores blood flow to the liver in patients with extrahepatic portal vein thrombosis. Stenosis occurs in some cases, causing the reappearance of portal hypertension. Complications such as thrombocytopenia present on a spectrum and there are currently no guidelines regarding a threshold for endovascular intervention. While Doppler ultrasound (US) is common for routine evaluation, magnetic resonance (MR) angiography with two-dimensional phase-contrast MRI (2-D PC-MRI) may improve the assessment of meso-Rex bypass function.

OBJECTIVES

To determine the feasibility and utility of MR angiography with 2-D PC-MRI in evaluating children with meso-Rex bypass and to correlate meso-Rex bypass blood flow to markers of portal hypertension.

MATERIALS AND METHODS

MR angiography and 2-D PC-MRI in meso-Rex bypass patients were retrospectively analyzed. Minimum bypass diameter was measured on MR angiography and used to calculate cross-sectional area. Meso-Rex bypass blood flow was measured using 2-D PC-MRI and divided by ascending aortic flow to quantify bypass flow relative to systemic circulation. Platelet and white blood cell counts were recorded. Correlation was performed between minimum bypass area, blood flow and clinical data.

RESULTS

Twenty-five children (median age: 9.5 years) with meso-Rex bypass underwent MR angiography and 2-D PC-MRI. The majority of patients were referred to imaging given clinical concern for complications. Eighteen of the 25 patients demonstrated >50% narrowing of the bypass cross-sectional area. The mean platelet count in 19 patients was 127 K/μL. There was a significant correlation between minimum cross-sectional bypass area and bypass flow (rho=0.469, P=0.018) and between bypass flow and platelet counts (r=0.525, P=0.021).

CONCLUSION

Two-dimensional PC-MRI can quantify meso-Rex bypass blood flow relative to total systemic flow. In a cohort of 25 children, bypass flow correlated to minimum bypass area and platelet count. Two-dimensional PC-MRI may be valuable alongside MR angiography to assess bypass integrity.

Porto-Rex Shunt for Left Portal Vein Reconstruction During Right Extended Hepatectomy for Advanced Extrahepatic Biliary Cancer

Resection offers the only chance of long-term survival or cure for perihilar cancer, provided R0 resection is achieved with margin-negative status of the remnant liver, bile duct, proximal hepatic artery, and portal vein. End-to-end anastomosis of the portal trunk to the left portal branch is the conventional portal reconstruction in cases of right extended hepatectomy requiring resection of the portal vein bifurcation. This mandatory reconstruction may be challenging due to (1) vessel incongruence, (2) fragility of the left portal branch wall, and more importantly, and (3) the divergent orientation of the two vessels exposing to vascular twisting/kinking. We report here the first two cases of porto-Rex shunt, between the portal vein trunk and the left portal vein in the umbilical fissure during right extended hepatectomy for advanced extrahepatic biliary cancer: one following failed conventional portal reconstruction and one to achieve macroscopically complete resection.

Clinical and Imaging Predictors of Surgical Splenorenal Shunt Dysfunction in Pediatric Patients

PURPOSE

Few established criteria exist to prompt angiographic evaluation and intervention for surgically created splenorenal shunts (SRS). Clinical and Doppler ultrasound (DUS) imaging predictors of shunt dysfunction were evaluated in this retrospective study.

MATERIALS AND METHODS

Consecutive patients undergoing SRS angiography over a 10-year period were retrospectively identified. Preangiography platelet count and DUS measurements of spleen diameter, maximum splenic vein velocity, and maximum shunt velocity were assessed and compared to findings at subsequent catheter angiography.

RESULTS

Twenty-six SRS angiograms were performed in 16 patients. Two of the 26 procedures were excluded from analysis due to insufficient baseline preangiography clinical and DUS data. In the remaining 24 cases, significant stenosis/occlusion was confirmed at angiography in 20, whereas wide patency was seen in 4. For the 20 cases of angiographically confirmed significant stenosis/occlusion, when compared to baseline post-SRS creation to immediate preangiography evaluation there was a greater decrease in platelet count (-51.8% vs -19.4%), a greater increase in spleen diameter (+13.4% vs +3.7%), a greater increase in maximum shunt velocity (+74.7% vs +59.7%), and a greater decrease in splenic vein velocity (-25.0% vs -18.5%).

CONCLUSION

Clinical evidence of splenic sequestration and DUS finding of increased maximum shunt velocity correlate with angiographic findings of SRS dysfunction and could be used to help predict the need for shunt intervention.

Pediatric Vascular Surgery Review with a 30-Year-Experience in a Tertiary Referral Center

Pediatric vascular disease is rare, and remains a big challenge to vascular surgeons. In contrast to adults, surgery for pediatric vascular disease is complicated by issues related to small size, future growth, and availability of suitable vascular conduit. During the last 30 years, 131 major vascular operations were performed in a tertiary referral center, Seoul National University Hospital, including aortoiliac aneurysm, acute or chronic arterial occlusion, renovascular hypertension, portal venous hypertension, trauma, tumor invasion to major abdominal vessels, and others. Herein we review on the important pediatric vascular diseases and share our clinical experiences on these rare diseases.

Evaluation of Rex Shunt on Cavernous Transformation of the Portal Vein in Children

BACKGROUND

Children with cavernous transformation of the portal vein (CTPV) develop severe complications from prehepatic portal hypertension, such as recurrent variceal bleeding and thrombocytopenia. In this study, we reported the results of 30 children with symptomatic CTPV that were treated by a Rex shunt. The effectiveness of this surgical approach was evaluated.

METHODS

A retrospective review was performed of 30 children aged between 3 and 18 years with CTPV, who underwent a Rex shunt between 2008 and 2015. All children were evaluated based on symptoms, complete blood count, portal system color-flow Doppler ultrasound or computed tomography angiography portography and gastroscopy for gastroesophageal varices pre- and postoperatively. Children were also evaluated during follow-up. Intraoperative evaluations included liver biopsy, portography and portal pressure.

RESULTS

Twenty-one patients demonstrated intermittent bleeding from gastroesophageal varices, 3 patients showed hypersplenism with varying degrees of leucopenia, anemia and thrombocytopenia, and in 6 patients both bleeding and hypersplenism were observed. Rex was successful in 28 patients (93.3%). The portal pressure immediately decreased significantly after placing of the shunt (P < 0.01). During the clinical follow-up period within 2-82 months, transaminase levels were maintained in the normal range. Blood flow velocity and diameter of the left portal vein significantly increased after surgery (P < 0.01). In addition, leukocyte and platelet counts increased postoperatively and anemia improved significantly (P < 0.01). Gastroscopy results indicated that the degree of gastroesophageal varices significantly alleviated postoperatively within 3 months and 1 year (P < 0.01). In 2 patients who demonstrated nodular cirrhosis and chronic active hepatitis, success of the Rex shunt was not achieved after operation. We found that for Rex effectiveness hepatic pathology and patient age were major determinants.

CONCLUSION

Rex shunt is an effective approach for the treatment of children suffering from CTPV at an early stage that do not show additional liver lesions.

Case report of a modified Meso-Rex bypass as a treatment technique for late-onset portal vein cavernous transformation with portal hypertension after adult deceased-donor liver transplantation

RATIONALE

Portal vein thrombosis is a complication after liver transplantation and cavernous transformation of the portal vein (CTPV) is a result of portal vein thrombosis, with symptoms of portal hypertension revealed by an enhanced CT scan. Meso-Rex bypass is an artificial shunt connecting the left portal vein to the superior mesenteric vein and is mainly used for idiopathic cavernomas. This technique is also used for post-transplant portal vein thrombosis in pediatric patients thereby bypassing obstructed sites of the extrahepatic portal vein. Here we report about an adult patient who was treated by connecting the cystic part of the portal vein to the splenic vein instead of the superior mesenteric vein.

PATIENTS CONCERN

An adult male patient with post-liver transplantation portal vein cavernous transformation suffered from hypersplenism and elevated hepatic enzymes.

DIAGNOSIS

The last follow up revealed irregular and obvious hypersplenism, and splenomegaly had occurred, while an enhanced CT scan revealed serious esophagogastric varices and CTPV in addition to occluded right and common PV trunks.

INTERVENTION

The patient was treated by connecting the cystic part of the portal vein to the splenic vein instead of the superior mesenteric vein.

OUTCOME

After the operation, a satisfactory velocity was confirmed 1 month postoperatively and the shunt still remained patent at the 6-month postoperation follow-up.

LESSONS

A Meso-Rex bypass intervention connecting the left portal vein to the splenic vein instead of the superior mesenteric vein after liver transplantation in an adult patient with right and common portal vein occlusions has been successfully performed as an alternative approach.

Extrahepatic Portal Vein Obstruction in Children: Role of Preoperative Imaging

Aim:

Extrahepatic portal vein obstruction (EHPVO) is characterized by features of recent thrombosis or portal hypertension with portal cavernoma as a sequel of portal vein obstruction. Imaging of spleno-portal axis is the mainstay for the diagnosis of EHPVO. The aim of this study is to analyze the role of imaging in the preoperative assessment of the portal venous system in children with EHPVO.

Materials and Methods:

A hospital-based cross-sectional study was conducted on twenty children with EHPVO aged between 1 and 18 years over a period of 1 year. The children were evaluated clinically, followed by upper gastrointestinal endoscopy. Radiological assessment included imaging of the main portal vein, its right and left branches, splenic vein, and superior mesenteric vein using color Doppler ultrasonography (CDUSG) and magnetic resonance portovenogram (MRP). Evidence of portal biliopathy, status of collaterals, and possible sites for portosystemic shunt surgery were also examined.

Results:

All the patients presented in chronic stage with portal cavernoma and only one patient (5%) had bland thrombus associated with cavernoma. The CDUSG and MRPs had a sensitivity of 66.6-90% and 96.7% and specificity of 91.5% and 98.3% respectively with regard to the assessment of the extent of thrombus formation and flow in the portal venous system. Both the modalities were found to be complementary to each other in preoperative assessment of EHPVO. However, the sensitivity of MRP was slightly superior to CDUSG in detecting occlusion and identifying portosystemic collaterals and dilated intrahepatic biliary radicals.

Conclusion:

Results of the present study indicate that MRP is well suited and superior to CDUSG in the preoperative imaging of patients with EHPVO.

Meso-Rex bypass to manage prehepatic portal hypertension after the failure of an intrahepatic portosystemic stent shunting

A cavernomatous transformation of the extrahepatic portion of the portal vein is a common cause of chronic portal hypertension in children. A few attempts at radiological interventions have been reported, but have rarely been successful. In this report, a surgical Meso-Rex bypass was performed to treat complicated prehepatic portal hypertension, after the insertion of an intrahepatic stent for portosystemic shunting had failed. The review of this case nicely illustrates how differently effective are these two shunting procedures-in terms of restoring hepatopetal flow, managing portal hypertension, and establishing-or not-portosystemic connections.

Intrahepatic portal venous systems in children with noncirrhotic prehepatic portal hypertension: anatomy and clinical relevance

BACKGROUND

Children with extrahepatic portal hypertension typically present with cavernomatous transformation of the portal vein and a poorly defined intrahepatic portal vein system on conventional imaging. With the Meso-Rex Bypass becoming the gold-standard intervention for a cure, a precise assessment of the intrahepatic portal vein system provides helpful data for deciding whether a Meso-Rex Bypass is feasible or not.

METHODS

All children with extrahepatic portal hypertension were prospectively assessed by wedged hepatic venous portography. Venous anatomy was categorized into five subtypes (A to E), depending on the presence of thrombosis in the Rex recessus, or not, and its extension within the intrahepatic portal venous system.

RESULTS

Eighty-nine children entered the study. Previous umbilical vein catheterization is usually associated with Rex thrombosis, while the Rex recessus and the intrahepatic portal venous system are patent in idiopathic cases, thus allowing for the performance of a Meso-Rex Bypass with a good outcome.

CONCLUSIONS

Wedged hepatic venous portography is a very effective tool for detailed preoperative assessment and identification of children being considered for Meso-Rex Bypass surgery. An anatomic-radiological classification is useful in selecting patients for Meso-Rex Bypass with anticipation of a high rate of success.

Imaging in clinical decision-making for portal vein thrombosis

Thrombosis of the portal venous system is a frequent and potentially life-threatening condition that can take place in a number of different clinical settings including liver cirrhosis, hepatocellular carcinoma, other solid tumours, abdominal septic foci, acute pancreatitis, haematological malignancies and congenital or acquired prothrombotic disorders. Clinical decision-making in patients with thrombosis of the portal venous system is a particularly complex process owing to the heterogeneity of the population affected by this condition and the lack of high-quality evidence from randomized controlled trials for the use of anticoagulation therapy in these patients. This Review discusses the available data regarding how imaging can provide assistance to physicians involved in this decision-making process in different clinical settings. A flowchart illustrating how to use imaging in this setting, based on current evidence and on the experience of the Vascular Liver Diseases Group of the Hospital Clinic in Barcelona, is also presented.

Prehepatic portal hypertension with aneurysm of the portal vein: unusual but treatable malformative pattern

INTRODUCTION

Portal vein aneurysms (PVAs) are usually located at the vein trunk or at its bifurcation, rarely intra-hepatic, or at the umbilical portion. Etiology remains unclear.

METHODS

Three children with PVA were identified over a 5-year period. PVA anatomy was assessed by Doppler Ultrasound, Angio CT/MRI, and trans-jugular retrograde portography.

RESULTS

Three children with intrahepatic PVA (including the umbilical portion) were identified during assessment for pre-hepatic portal hypertension: all had splenomegaly and hypersplenism. One presented with massive variceal bleeding. In two cases, a portal vein cavernoma was found, and in the third a severe stricture at the portal bifurcation was observed. Restoration of portal venous flow was achieved by a meso-Rex bypass in two cases and transposing the PV into the Rex in one. High hepatopetal portal flow was restored immediately, with follow-up confirming long-term patency and resolution of signs of portal hypertension with time.

CONCLUSIONS

These original observations suggest a common initial malformative pattern consisting of a portal venous stricture/web causing a post-stenotic aneurysmal dilatation of the intrahepatic portal branches complicated by thrombosis and cavernomatous transformation of the portal vein trunk. Importantly, the Meso-Rex bypass allows restoring a normal portal flow and cures the portal hypertension.

Renal blood flow before and after portosystemic shunt in children with portal hypertension

INTRODUCTION

Variceal haemorrhage in children with extrahepatic portal hypertension is best controlled by an effective decompressive shunt, but long-term follow up of children who have had splenorenal shunt due to extrahepatic portal hypertension (EHPH) gave evidence for assuming the risk of renal venous hypertension (RVH).

PURPOSE

To study renal hemodynamic before and after portal decompression.

METHODS

The results of 144 portosystemic shunt operations were followed from 2005 to 2013. Seventy-two patients applied central splenorenal shunt (CSS) with splenectomy, ten side-to-side splenorenal shunt without splenectomy (SRSss), ten patients assessed the distal splenorenal shunt (DSS). Forty-three iliacomesenterial anastomosis (IMA) and in nine cases performed mesocaval anastomosis (MCA). Children had a standard pre- and postoperative work up including gastrointestinal endoscopy, Doppler ultrasonography (US), multi-slice computed tomography (MSCT) and renography.

RESULTS

In 11 (15.2 %) patients after CSS on duplex, Doppler study revealed signs of impeded venous outflow on the left renal vein (LRV). At long-term follow-up PI and RI of left renal artery remained at high numbers (1.48 ± 0.17 and 0.72 ± 0.19, p ≤ 0.05, respectively) after the CSS. Venous blood flow in the LRV at the hilum showed slower speed performance in groups of CSS and after IMA. After DSS, these signs have not been detected. Four patients after IMA on US Doppler and CT angiography revealed dilated left testicular and ovarian veins, with retrograde blood flow in them, which clinically manifested as left flank pain, macro- and microhematuria, varicocele and ovaricocele.

CONCLUSION

The study shows that CSS and IMA more negatively effect on hemodynamics of left kidney and symptoms of RVH obviously due to shunting the large amounts of blood from a system of high pressure to a low.

Results of a stepwise approach to extrahepatic portal vein obstruction in children

BACKGROUND

The management of extrahepatic portal vein obstruction (EHPVO) in children is controversial. We report our experience with a prospective evaluation of a stepwise protocol based on severity of portal hypertension and feasibility of mesoportal bypass (MPB).

METHODS

After diagnosis, children with EHPVO underwent surveillance endoscopies and received nonselective β-blockers (NSBBs) or endoscopic variceal obliteration (EVO) when large varices were detected. In patients who failed NSBBs and EVO, we considered MPB as first-line and shunts or transjugular intrahepatic portosystemic shunt (TIPS) as second-line options.

RESULTS

Sixty-five children, median age 12.5 (range 1.6-25.8), whose age at diagnosis was 3.5 (0.2-17.5) years, were referred to our unit. Forty-three (66%) had a neonatal illness, 36 (55%) an umbilical vein catheterisation. Thirty-two (49%) presented with bleeding at a median age of 3.8 years (0.5-15.5); during an 8.4-year follow-up period (1-16), 43 (66%) had a bleeding episode, 52 (80%) were started on NSBBs, 55 (85%) required EVO, and 33 (51%) required surgery or TIPS. The Rex recessus was patent in 24 of 54 (44%), negatively affected by a history of umbilical catheterisation (P = 0.01). Thirty-four (53%) patients underwent a major procedure: MPB (13), proximal splenorenal (13), distal splenorenal (2), mesocaval shunt (3), TIPS (2), and OLT (1). At the last follow-up, 2 patients died, 53 of 57 (93%) are alive with bleeding control, 27 of 33 (82%) have a patent conduit.

CONCLUSIONS

Children with EHPVO have a high rate of bleeding episodes early in life. A stepwise approach comprising of medical, endoscopic, and surgical options provided excellent survival and bleeding control in this population.

Perioperative strategies and thrombophilia in children with extrahepatic portal vein obstruction undergoing the meso-Rex bypass

BACKGROUND/PURPOSE

Extrahepatic portal vein obstruction (EHPVO) is an important cause of chronic portal hypertension in children. Although usually idiopathic in etiology, genetic and acquired thrombophilia have been implicated in EHPVO. Meso-Rex bypass is increasingly used to treat EHPVO in children.

OBJECTIVE

The objective of this study is to assess the relationship of postoperative anticoagulation strategies and thrombophilic risk factors to the development of bypass thrombosis following the meso-Rex bypass.

METHODS

Records of children who underwent meso-Rex bypass for EHPVO at a single institution from 1999 to 2009 were reviewed, and preoperative thrombophilia testing, perioperative anticoagulation strategies, and postoperative bypass patency based on imaging at last follow-up were examined.

RESULTS

Sixty-five children with EHPVO underwent a first time meso-Rex bypass during the study period, and 9 of 65 (14 %) developed bypass thrombosis. The use of warfarin in the postoperative period was more common among children with thrombosed shunts than among those with open shunts [63 % vs. 20 %; OR, 6.5 (95 % CI, 1.3-31.5), p = 0.022]. The contribution of genetic or acquired thrombophilia to shunt thrombosis was inconclusive given variability in testing.

CONCLUSIONS

Choice of anticoagulation following meso-Rex bypass may affect postoperative incidence of bypass thrombosis. Role of thrombophilic risk factors in the development of shunt thrombosis remains unclear.

Meso-Rex bypass as an alternative technique for portal vein reconstruction at or after liver transplantation in children: review and perspectives

Direct portal revascularization can be achieved by interposing a vascular graft between the SMV and the Rex recessus (left portal vein system): the MRB. To review indications and results of the procedure in the setting of pediatric liver transplantation, reports were selected from the English literature. Previously reported series were updated to analyze long-term outcome. A new series was added and analyzed as a complementary set of cases. A total of 51 cases were analyzed. With a 96% overall patient survival rate and a 100% long-term patency rate when the IJV is used for the bypass, MRB achieves a very successful physiologic cure of chronic portal hypertension and restores the portal flow into and through the liver graft. It also has been used successfully for primary revascularization of liver grafts, as well as for managing early acute portal vein thrombosis episodes. The use of this procedure in conjunction with other strategies and techniques might be of interest for transplant surgeons, particularly those caring for children.

Pathophysiologie der Leberkrankheiten

In der sinusoidalen Membran beginnt die Gallebildung. Rezeptoren und Transporter erleichtern die Aufnahme und den Eintritt von Gallensäuren, Bilirubin, Fettsäuren und anderen Gallekomponenten in die Leberzelle. Diese enthält Rezeptoren für Glykoproteine, Asialoglykoprotein, Immunglobulin A (Ig A), vasoaktives intestinales Peptid (VIP), Insulin, Glukagon und „epidermal growth factor“ (EGF). Ein primär aktiver Transport erfolgt durch die Na+-K+-ATPase, die einen Ionengradienten an der Zellmembran aufbaut und innerhalb der Zelle ein negatives elektrisches Potenzial erzeugt (wodurch die Diffusion erleichtert wird). Dieser Ionengradient ermöglicht die Arbeit anderer Carrier gegen das Konzentrationsgefälle, z. B. von NTCP (Natrium-Taurocholsäure-Kotransport-Polypeptid), das auch für zahlreiche Medikamente, Östrogene und zyklische Oligopeptide spezifisch ist. Transporter für organische Anionen (OATP1) und anorganische Ionen wurden ebenfalls nachgewiesen.

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.

Warren shunt combined with partial splenectomy for children with extrahepatic portal hypertension, massive splenomegaly, and severe hypersplenism

PURPOSE

To establish the importance of shunt surgery combined with partial resection of the spleen for selected pediatric patients with extra-hepatic portal vein obstruction (EHPVO), enormous splenomegaly and severe hypersplenism. Severe hypersplenism is often refractory to treatment with endoscopic sclerotherapy or band ligation and shunt surgery; however, to our knowledge, this is the first such study to be published.

METHODS

Distal splenorenal shunt with partial resection of the spleen was performed in 16 of 60 children treated for EHPVO in the Gastroenterology Department of our hospital. Upper gastrointestinal endoscopy had shown esophageal varices of varying grade in all patients and band ligation or endoscopic sclerotherapy had been done for children with a history of bleeding. The indications for surgery were pain and discomfort caused by a large spleen (5-15 cm below the costal margin) and symptomatic hypersplenism with leucopenia, thrombocytopenia, and anemia. Partial resection of the spleen was performed, starting with ligation of the branches and tributaries of the caudal two-thirds. When an ischemic line demarcated the splenic parenchyma, it was transected using electrocautery or LigaSure, leaving 20-30 % of splenic tissue. After the spleen resection, a Warren shunt was performed. Platelet and white blood cell counts and liver function tests were performed before and after the operation. Growth was assessed using SD scores (z scores) for height, weight, and body mass index at the time of surgery and 1 year later.

RESULTS

Postoperative recovery was uneventful and the leukocyte and platelet counts normalized. The shunt patency rate was 100 %. Two cases of shunt stenosis were treated successfully with percutaneous angioplasty. There was no postoperative mortality. During the follow-up period, from 1 to 7 years, all 16 children were asymptomatic, with improved quality of life, growth, and nutrition. No episodes of variceal bleeding, sepsis or encephalopathy occurred.

CONCLUSION

Our results demonstrate that shunt surgery with partial resection of the spleen is effective and safe for pediatric patients with massive splenomegaly and severe hypersplenism secondary to EHPVO.

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.

Pre- and postoperative imaging and interventions for the meso-Rex bypass in children and young adults

The meso-Rex bypass is a physiological and anatomical bypass procedure for relief of extrahepatic portal vein obstruction and restoration of mesenteric venous return to the liver. Most patients who are candidates for the bypass are children or young adults with portal hypertension and hypersplenism secondary to cavernous transformation of the portal vein. Most frequently, the bypass utilizes an autologous venous graft to connect the intrahepatic left portal vein to the infrapancreatic superior mesenteric vein (SMV) re-establishing first-pass portal perfusion. We describe the preoperative imaging of the 92 bypass candidates, the surgical anatomy as reflected in postoperative imaging, and the imaging of bypass complications at our institution.Preoperative imaging with US, CT and MR is directed to demonstrate patency and size of the left portal vein and SMV, to define the extent of cavernous transformation and splanchnic collaterals, and to assess for any associated abdominal vascular or solid organ abnormalities. Postoperative imaging is aimed at diagnosing meso-Rex bypass stenosis or occlusion and the interventional management of these complications.

Medical management of chronic liver diseases (CLD) in children (part II): focus on the complications of CLD, and CLD that require special considerations

Treatment of the causes of many chronic liver diseases (CLDs) may not be possible. In this case, complications must be anticipated, prevented or at least controlled by the best available therapeutic modalities. There are three main goals for the management of portal hypertension: (i) prevention of the first episode of variceal bleeding largely by non-selective β-adrenoceptor antagonists, which is not generally recommended in children; (ii) control of bleeding by using a stepwise approach from the least to most invasive strategies; (iii) and prevention of re-bleeding using bypass operations, with particular enthusiasm for the use of meso-Rex bypass in the pediatric population. Hepatic encephalopathy management also consists of three main aspects: (i) ruling out other causes of encephalopathy; (ii) identifying and treating precipitating factors; and (iii) starting empiric treatment with drugs such as lactulose, rifaximin, sodium benzoate, and flumazenil. Treatment of mild ascites and peripheral edema should begin with the restriction of sodium and water, followed by careful diuresis, then large-volume paracentesis associated with colloid volume expansion in severe cases. Empiric broad spectrum antimicrobial therapy should be used for the treatment of spontaneous bacterial peritonitis, bacterial and fungal sepsis, and cholangitis, after taking appropriate cultures, with appropriate changes in therapy after sensitivity testing. Empirical therapies continue to be the standard practice for pruritus; these consist of bile acid binding agents, phenobarbital (phenobarbitone), ursodeoxycholic acid, antihistamines, rifampin (rifampicin), and carbamazepine. Partial external biliary diversion can be used in refractory cases. Once hepatorenal syndrome is suspected, treatment should be initiated early in order to prevent the progression of renal failure; approaches consist of general supportive measures, management of concomitant complications, screening for sepsis, treatment with antibiotics, use of vasopressin analogs (terlipressin), and renal replacement therapy if needed. Hepatopulmonary syndrome and portopulmonary hypertension are best managed by liver transplantation. Provision of an adequate caloric supply, nutrition, and vitamin/mineral supplements for the management of growth failure, required vaccinations, and special care for ensuring psychologic well-being should be ensured. Anticoagulation might be attempted in acute portal vein thrombosis. Some CLDs, such as extrahepatic biliary atresia (EHBA), Crigler-Najjar syndrome, and Indian childhood cirrhosis, require special considerations. For EHBA, Kasai hepatoportoenterostomy is the current standard surgical approach in combination with nutritional therapy and supplemental fat and water soluble vitamins, minerals, and trace elements. In type 1 Crigler-Najjar syndrome, extensive phototherapy is the mainstay of treatment, in association with adjuvant therapy to bind photobilirubin such as calcium phosphate, cholestyramine, or agar, until liver transplantation can be carried out. Treating Indian childhood cirrhosis with penicillamine early in the course of the disease and at doses similar to those used to treat Wilson disease decreases the mortality rate by half. New hopes for the future include extracorporeal liver support devices (the molecular adsorbent recirculating system [MARS®] and Prometheus®), hepatocyte transplantation, liver-directed gene therapy, genetically engineered enzymes, and therapeutic modalities targeting fibrogenesis. Hepapoietin, a naturally occurring cytokine that promotes hepatocyte growth, is under extensive research.