Variation of the Rex shunt for treating concurrent obstruction of the portal and superior mesenteric veins

Children with extrahepatic portal vein obstruction can be managed successfully by surgical intervention and should be evaluated for potential meso-Rex bypass. A Rex shunt variation is described to treat portal and superior mesenteric vein thrombosis. This technique uses the internal jugular vein as a conduit between the splenic vein and the left portal vein with splenic preservation.     

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 Shunt Using Deep Femoral Vein Conduit: First Report

The Meso-Rex shunt (MRS) procedure was first described in 1992 by de Ville et al. for the treatment of extra-hepatic portal vein obstruction (EHPVO) in paediatric liver transplant patients (1). This technique provides more physiological relief of portal hypertension compared to the porto-systemic shunts, which can lead to long-term complications such as hyperammonaemia and hepato-pulmonary syndrome (2). Different conduits as autologous and cryopreserved veins or prosthetic grafts have been previously reported (3–7). We present herein the first case of a MRS using the autologous deep femoral vein in a 17-year-old female patient affected by EHPVO from unknown reasons.     

Preoperative imaging of left portal vein at the Rex recess for Rex shunt formation using wedged hepatic vein carbon dioxide portography

Background

In children with extrahepatic portal vein obstruction (EHPVO), formation of a mesentericoportal bypass (Rex shunt) restores hepatopetal flow, relieves portal hypertension, and reduces variceal bleeding and hypersplenism. The Rex shunt is created by inserting a vein graft between the superior mesenteric vein and the umbilical segment (Rex) of the left portal vein within the Rex recess of the liver. The preoperative evaluation of a patient with EHPVO includes an accurate assessment of the venous inflow and outflow. The inflow portal vein is readily assessed by ultrasound and magnetic resonance imaging. The outflow intrahepatic portal vein is harder to assess. We report our experience of patients evaluated with wedged hepatic vein carbon dioxide portography (WHVCP).

Method

All children referred for venography from October 2001 to October 2007 were prospectively identified, and clinical and radiologic data were reviewed retrospectively. The imaging findings were correlated to findings at surgery.

Results

Eleven children (range, 3-14 years, median, 6 years) were referred for preoperative wedged hepatic venography. The left portal vein at the Rex recess was clearly identified in 9 patients (82%). In the other 2 patients (18%), the Rex segment was not identified despite opacification of left and right intrahepatic portal veins; this was taken to indicate an occluded segment. Wedged venography was performed with carbon dioxide in 10 patients (91%). Carbon dioxide was contraindicated in the final patient because of the presence of a ventricular septal defect.

Conclusion

Our series demonstrates the use of WHVCP as a diagnostic tool in preoperative assessment of the Rex segment of left portal vein in children with extrahepatic portal vein obstruction.     

Living Donor Liver Transplantation for Congenital Absence of the Portal Vein

The congenital absence of the portal vein (CAPV) is a rare venous malformation in which mesenteric venous blood drains directly into the systemic circulation. Liver transplantation (OLT) may be indicated for patients with symptomatic CAPV refractory to medical treatment, especially due to hyperammonemia, portosystemic encephalopathy, hepatopulmonary syndrome, or hepatic tumors. Because portal hypertension and collateral circulation do not occur with CAPV, significant splanchnic congestion may occur when the portocaval shunt is totally clamped during portal vein (PV) reconstruction in OLT. This phenomenon results in severe bowel edema and hemodynamic instability, which negatively impact the patient's condition and postoperative recovery. We have successfully reconstructed the PV in living donor liver transplantation (LDLT) using a venous interposition graft, which was anastomosed end-to-side to the portocaval shunt by a partial side-clamp, using a patent round ligament of the liver, which was anastomosed end-to-end to the graft PV with preservation of both the portal and caval blood flows. Owing to the differences in anatomy among patients, at LDLT for CAPV liver transplant surgeons should seek to preserve both portal and caval blood flows.     

成人肝外型门静脉高压症诊治分析

目的: 探讨成人肝外型门静脉高压症(EHPH)的临床特点和治疗策略. 方法: 回顾分析对6例EHPH病人的诊治过程. 结果: 5例病人以反复上消化道出血及脾亢为主要临床表现,经彩色多普勒超声及门静脉造影检查,3例有典型门静脉海绵样变(CTPV)表现,1例为门静脉血栓形成,1例为卵巢癌转移压闭脾静脉.断流术3例,肠腔分流术1例,内镜下曲张静脉硬化及结扎治疗2例,平均随访8.4个月,死亡2例. 结论: 成人EHPH病因复杂,诊断主要依靠彩超及门静脉造影,治疗方案根据病人具体情况而定.     

Management of Variceal Hemorrhage in Children with Extrahepatic Portal Venous Obstruction-Shunt Surgery Versus Endoscopic Sclerotherapy

Extrahepatic portal venous obstruction (EHPVO) is a common cause of portal hypertention in children. Esophageal variceal hemorrhage is a major cause of morbidity and mortality in these patients. For many decades, portal systemic shunts were considered as the most effective treatment of variceal hemorrhage. Endoscopic injection sclerotherapy (EIS) was first introduced for emergency management of bleeding varices and subsequently as definitive treatment to prevent recurrent hemorrhage. The purpose of the study was to compare the safety and efficacy of shunt surgery and endoscopic sclerotherapy for patients with proven esophageal variceal bleeding due to EHPVO. The study was a prospective randomized study of 61 children with bleeding esophageal varices due to EHPVO carried out jointly by the department of General Surgery and Gastroenterology at Sher-i-Kashmir Institute of Medical Sciences, Srinagar, between March 2001 and September 2003. Thirty patients received surgery and other 31 patients received EIS. Overall incidence of rebleeding was 22.6% in sclerotherapy group and 3.3% in shunt surgery group. Treatment failure occurred in 19.4% patients in sclerotherapy group and 6.7% in shunt surgery group. The rebleeding rate of sclerotherapy is significantly higher than that of shunt surgery. However, the therapy failure rate of sclerotherapy is not significantly different from that of shunt surgery.     

Experience with alternate sources of venous inflow in the meso-Rex bypass operation: the coronary and splenic veins

The meso-Rex bypass procedure has been used to treat patients with portal hypertension from extrahepatic portal vein obstruction. This report describes modifications of this procedure in 5 patients. Either the splenic or coronary vein was used as the venous inflow point, and the bypass was performed either directly through transposition of the vein or with the use of a venous conduit.     

门静脉和肠系膜上静脉血栓形成的CT、MRI诊断

目的探讨门静脉（PV）和肠系膜上静脉（SMV）血栓形成的CT、MRI征象及其诊断价值。方法回顾性分析25例经手术与病理证实的PV-SMV血栓形成病例CT和MRI检查资料。结果PV-SMV血栓形成的直接征象CT表现为PV-SMV血管内充盈缺损,PV周围呈轨道样增强;MRI表现为PV和SMV正常流空信号消失;急性、亚急性期血栓T1WI呈等或高信号,T2WI呈高信号;GD-DTPA增强扫描静脉期PV-SMV管腔内对比剂充盈缺损。PV-SMV血栓形成的间接征象包括肠腔扩张积液,肠管积血,肠壁增厚,肠黏膜水肿,薄纸样肠壁,缆绳征,肠系膜积液,肠壁积气,腹腔积液,门静脉海绵样变,肝脏异常灌注。结论CT、MRI是诊断PV-SMV血栓形成最有效的影像检查方法,MRI对PV-SMV血栓形成的定位、定量及血栓的分期优于CT。     

Auxiliary partial orthotopic living donor liver transplantation for a child with congenital absence of the portal vein.

Congenital absence of the portal vein (CAPV) is a rare malformation of the mesenteric vasculature in which visceral venous blood bypasses the liver, completely draining into the systemic circulation through a congenital porto-systemic shunt. Liver transplantation has rarely been indicated for patients with this disease. We present a child with CAPV who was managed successfully by living donor auxiliary partial orthotopic liver transplantation (APOLT), while preserving the right lobe of the native liver. In conclusion, APOLT for patients with CAPV is a feasible and ideal procedure because portal vein (PV) diversion is not necessary.     

Portal-to-right portal vein bypass for extrahepatic portal vein obstruction

Objective

Rex shunt (mesenteric-to-left portal vein bypass) is considered a more physiologically rational treatment for EHPVO than other portosystemic systemic shunts in children. However, about 13.6% of children with EHPVO do not have usable left portal veins and up to 28.1%. Rex operations in children are not successful. Hence, a Rex shunt in these children was impossible. This study reports a novel approach by portal-to-right portal vein bypass for treatment of children with failed Rex shunts.

Gastroportal shunt for portal hypertension in children

PurposeExtrahepatic portal venous obstruction is the most common cause of portal hypertension in children. The Rex shunt has been used successfully to treat patients with extrahepatic portal hypertension. In the conventional Rex shunt, the internal jugular vein is used as a venous graft. Inevitably, such a procedure requires neck exploration and sacrifice of internal jugular vein. The authors describe a novel adaptation of gastroportal shunt, successfully carried out in 8 children with extrahepatic portal hypertension.MethodsThe mean age of the 8 patients (6 boys and 2 girls) was 66.6 months at the time of operation. All children had portal hypertension. Seven had a history of upper gastrointestinal bleeding, and 4 had splenomegaly and hypersplenism. Gastroportal shunt was performed in all patients. The left gastric vein was mobilized and anastomosed to left portal vein. In 1 patient, the left gastric vein was not of adequate length and required a venous graft (the inferior mesenteric vein). All patients were followed up for 3 to 20 months (median, 9 months).ResultsThe gastroportal shunt was successfully performed in all patients. The median operative time was 265 minutes (range, 205-360 minutes). Operative blood loss was 21 ± 7.4 mL, and the length of hospital stay varied from 9 to 19 days (median, 15 days). Intraoperative portal venous angiography demonstrated the patency of the shunt in all patients. Postoperatively, the complete blood count normalized, and the biochemistry tests were within reference range. Postoperative ultrasound confirmed shunt patency and satisfactory flow in the gastroportal shunt in each patient. The size of spleen decreased. There was no recurrence of variceal bleeding.ConclusionsThe gastroportal shunt is an effective treatment of extrahepatic portal hypertension.     

Pathological abnormalities in splenic vasculature in non-cirrhotic portal hypertension:Its relevance in the management of portal hypertension

BACKGROUND Portal hypertension(PH) is associated with changes in vascular structure and function of the portosplenomesenteric system(PSMS).This is referred to as portal hypertensive vasculopathy.Pathological abnormalities of PSMS has been described in the literature for cirrhotic patients.Raised portal pressure and hyperdynamic circulation are thought to be the underlying cause of this vasculopathy.In view of this,it is expected that pathological changes in splenic and portal vein similar to those reported in cirrhotic patients with PH may also be present in patients with non-cirrhotic PH(NCPH).AIM To investigate pathological abnormalities of splenic vein in patients with NCPH,and suggest its possible implications in the management of PH.METHODS A prospective observational study was performed on 116 patients with NCPH[Extrahepatic portal vein obstruction(EHPVO):53 and non-cirrhotic portal fibrosis(NCPF):63] who underwent proximal splenorenal shunt(PSRS),interposition shunt or splenectomy with devascularization in JIPMER,Pondicherry,India,a tertiary level referral center,between 2011-2016.All patients were evaluated by Doppler study of PSMS,computed tomography portovenogram and upper gastrointestinal endoscopy.An acoustic resonance forced impulse(ARFI) scan and abdomen ultrasound were done for all cases to exclude cirrhosis.Intraoperative and histopathological assessment of the harvested splenic vein was performed in all.The study group was divided into delayed and early presentation based on the median duration of symptoms(i.e.108 mo).RESULTS The study group comprising of 116 patients [77(66%) females and 39(34%)males] with NCPH had a median age of 22 years.Median duration of symptoms was 108 mo.The most common presentation in both EHPVO and NCPF patients was upper gastrointestinal bleeding(hematemesis and melena).The ARFI scan revealed a median score of 1.2(1.0-1.8) m/s for EHPVO and 1.5(0.9-2.8) m/s for NCPF.PSRS was performed in 84 patients(two of whom underwent interposition PSRS using a 10 mm Dacron graft);splenoadrenal shunt in 9;interposition mesocaval shunt in 5;interposition 1 st jejunal to caval shunt in 1 patient and devascularization with splenectomy in 17 patients.Median presplenectomy portal pressure was 25(range:15-51) mm Hg.In 77% cases,the splenic vein was abnormal upon intraoperative assessment.Under macroscopic examination,wall thickening was observed in 108(93%),venous thrombosis in 32(28%) and vein wall calcification in 27(23%) cases.Upon examination under a surgical magnification loupe,21(18%) patients had intimal defects in the splenic vein.Histopathological examination of veins was abnormal in all cases.Medial hypertrophy was noted in nearly all patients(107/116),while intimal fibrosis was seen in 30%.Ninety one percent of patients with intimal fibrosis also had venous thrombosis.Vein wall calcification was found in 22%,all of whom had intimal fibrosis and venous thrombosis.The proportion of patients with pathological abnormalities in the splenic vein were significantly greater in the delayed presentation group as compared to the early presentation group.CONCLUSION Pathological changes in the splenic vein similar to those in cirrhotic patients with PH are noted in NCPH.We recommend that PH in NCPH be treated as systemic and pulmonary hypertension equivalent in the gastrointestinal tract,and that early aggressive therapy be initiated to reduce portal pressure and hemodynamic stress to avoid potential lethal effects.     

肠系膜静脉血栓的介入治疗

目的探讨经肠系膜上动脉灌注罂粟碱和经皮经肝肠系膜静脉取栓和／或溶栓联合治疗肠系膜静脉血栓（MVT）的价值。方法回顾分析北大三院经介入诊治的9例MVT。9例患者均行血管造影检查和超声检查，其中5例行CT检查，2例行MR检查。患者从就诊到明确诊断接受介入治疗的时间间隔为15～168小时。明确诊断MVT后即经外周静脉给予肝素抗凝治疗；9例MVT均行经肠系膜动脉灌注罂粟碱治疗，其中8例同时行经皮经肝门静脉、肠系膜上静脉取栓和溶栓治疗。2例怀疑肠坏死介入治疗后行外科肠切除术。结果本组9例MVT中2例血栓局限在肠系膜上静脉内；7例血栓延及门静脉或脾静脉。9例患者7例治愈；1例不明原因猝死；1例因门脉高压行门腔静脉分流术后肝功衰竭死亡。结论经肠系膜动脉灌注罂粟碱联合经皮经肝门静脉、肠系膜静脉取栓和／或溶栓是治疗MVT的有效方法。     

Previous portal hypertension surgery negatively affects results of mesenteric to left portal vein bypass

Purpose

The mesenteric to left portal vein bypass (MLPVB) has been successfully used to treat extrahepatic portal vein obstruction (EHPVO) in children. We examined the effect of failed prior surgical or radiological procedures intended to treat complications of portal hypertension on the success rate of subsequent MLPVB surgery.

Methods

Sixty-two patients younger than 18 years with EHPVO underwent MLPVB between 1997 and 2006. Children were divided into 3 groups: those with no prior surgery related to portal hypertension, those with prior portosystemic shunts, and those with either splenectomy or mesenteric vascular embolization procedures. The effect of prior procedures on the patency rate of the MLPVB was then examined.

Results

Of 62 children, 11 (17.7%) had significant procedures to treat symptoms of portal hypertension: 6 had at least 1 portosystemic shunt attempt, 3 had isolated splenectomy, and 2 had embolization of the splenic artery or coronary and peripancreatic varices. Patients with previous portal hypertension surgery were significantly older and larger than those with no surgery. Patients with no prior interventions had a significantly higher MLPVB patency rate (88.2%, 45/51) than those with no prior interventions (63.6%, 7/11). Prior splenectomy alone was not found to adversely affect MLPVB. Patients with prior embolization procedures or unsuccessful shunts had significantly poorer successful outcomes (0% and 66.7%) than those with no prior interventions (88.2%; P < .005).

Conclusions

The results demonstrate that prior portosystemic shunts or mesenteric embolizations have a deleterious effect on outcome after MLPVB and should be avoided whenever possible. This study suggests that patients with symptomatic EHPVO should undergo MLPVB as a primary intervention rather than as a rescue procedure to optimize MLPVB patency.     

H-type shunt with an autologous venous graft for treatment of portal hypertension in children

From 1981 to 1987, 86 children aged 16 months to 16 years underwent a portosystemic shunt procedure using an autologous venous graft (internal jugular vein in 80 cases). Fifty-five mesocaval, 20 splenorenal, 4 portacaval, and 7 makeshift shunts were constructed. The indication for shunting was an extrahepatic portal obstruction in 59 cases, intrahepatic portal obstruction in 23 cases (including 6 cases of congenital hepatic fibrosis), and Budd-Chiari syndrome in 4 cases. One patient of the latter group died early from intractable ascites with a nonfunctioning shunt, and a second child died 2 months after operation from unknown reasons with a patent shunt. With a follow-up over 1 year for 58 of the 84 survivors, 78 successes and 6 failures were recorded according to the clinical outcome and the findings of ultrasonic and endoscopic examinations. Three of the six children with a failed shunt have been submitted to a second successful H-type shunt operation. No case of encephalopathy was recorded in this series. Thus, with an approximate success rate of 95%, the H-type shunt with a venous graft should be recommended for treatment of portal hypertension of extrahepatic origin, especially in young children.     

Early Vein Reconstruction and Right-to-Left Dissection for Left-Sided Pancreatic Tumors with Portal Vein Occlusion

Large left-sided pancreatic tumors are frequently associated with portal vein (PV) and/or superior mesenteric vein (SMV) occlusion. Traditionally, vein reconstruction is deferred until after removal of the tumor. However, division of venous collaterals, as is done in a typical left-to-right fashion, leads to progressive portal hypertension and increased risk of variceal hemorrhage during the dissection. Conversely, early PV/SMV resection and reconstruction restores mesenteric-portal flow and decompresses varices, thereby enabling a safer and easier right-to-left pancreatic resection. This “How I Do It” report describes the technique and advantages of a “reconstruction-first” approach for large left-sided pancreatic tumors with venous involvement and left-sided portal hypertension.     

Extrahepatic portal hypertension treated by anastomosing inferior mesenteric vein to left portal vein at Rex recessus

For the treatment of recurrent bleeding despite sclerotherapy or clinically significant hypersplenism, portosystemic shunt procedures should be performed in cases of extrahepatic portal hypertension caused by extrahepatic portal vein thrombosis. A novel alternative to portosystemic shunt procedures in extrahepatic portal hypertension is mesenterico-left portal bypass. Portal vein thrombosis is bypassed by an autologous vein graft (usually left internal jugular vein) interposed between superior mesenteric vein and left portal vein. In the presence of an enlarged right gastroepiploic vein, the distal end of this vein can be anastomosed to left portal vein without disturbing its proximal end. Herein, the authors report a case of extrahepatic portal hypertension treated by anastomosing enlarged inferior mesenteric vein to left portal vein to bypass portal vein thrombosis.     

Immediate and long-term results of superior mesenteric vein-inferior vena cava shunt for portal hypertension in children.

Experience with 46 superior mesenteric vein-inferior vena cava shunts in children is reported, with postoperative follow-up of from 2 to 15 yr. The first procedure used as an end-to-side implantation of the vena cava into the right side of the superior mesenteric vein or portal vein after ligating the cava above the iliac vessels (16 cases). In the next 30 children, the vena cava was lengthened using the left or right common iliac vein, thus obtaining better anastomosis and reversed portal flow. Patency may be definitely assumed when the esophageal varices have disappeared within 3 mo; this was observed in 33 children. Results are nearly the same with superior mesenteric vein-inferior vena cava shunt, splenorenal shunt and portacaval shunt when the respective veins of the portal system are more than 1 cm in diameter. When it is less, the superior mesenteric vein-inferior vena cava shunt is more successful than others; this is the case in children under 7 yr of age. No serious trouble was observed after the interruption of the venous circulation of the limbs and pelvis when a superior mesenteric vein-inferior vena cava shunt was performed when the patients were less than 15 yr of age.     

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.