Multimodality imaging of the Meso-Rex bypass

Pediatric liver cirrhosis interventional procedures: from biopsy to transjugular intrahepatic portosystemic shunt

Cirrhosis is a complex diffuse process whereby the architecture of the liver is replaced by abnormal nodules because of the presence of fibrosis. Several pediatric diseases such as extrahepatic portal vein obstruction, biliary atresia, alpha-1-antitrypsin deficit and autoimmune hepatitis can lead to cirrhosis and portal hypertension in children. In this article the authors describe interventional radiology procedures that can facilitate the diagnosis and treatment of diseases associated with liver cirrhosis and portal hypertension in the pediatric population. These procedures include image-guided liver biopsy, mesenteric-intrahepatic left portal vein shunts, balloon-occluded retrograde transvenous obliteration, transjugular intrahepatic portosystemic shunts and splenic embolization.

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 Role of Imaging in Portal Vein Thrombosis: From the Diagnosis to the Interventional Radiological Management

PURPOSE

To illustrate diagnostic and interventional imaging for the characterization and treatment of portal vein thrombosis (PVT).

INTRODUCTION

The broad spectrum of congenital and acquired PVT manifestations is illustrated, with a focus on the pediatric population; diagnostic and interventional imaging techniques are described.

DESCRIPTION

PVT frequently presents as an incidental finding at imaging in the screening for liver diseases or for other unrelated reasons. PVT can be classified based on: extension (intrahepatic, extrahepatic, involving the spleno-mesenteric tract, etc.); degree (partial or complete); onset (acute or chronic); and with or without cavernomatous transformation. This comprehensive review relies on the experience gained from a large series of congenital and acquired PVT in a referral center for pediatric and adult liver transplantation. Diagnostic and interventional imaging techniques are described, including: color-Doppler and contrast-enhanced Ultrasound; CT and MR angiography; retrograde portography; percutaneous transhepatic, transplenic, and transmesenteric portography; transjugular intrahepatic portosystemic shunt creation. Pre- and post-operative imaging assessment of the surgical meso-rex bypass is discussed. The description is enriched with an original series of pictorial imaging findings.

CONCLUSION

PVT is a clinical condition associated with significant morbidity and mortality. Diagnostic and interventional imaging plays a crucial role in both conservative and operative management.

Comparison of sequential CT arterioportography-arteriosplenography with standard cross-sectional imaging and endoscopy in children with portal hypertension

In this study the diagnostic capability and additional value of sequential CT arterioportography–arteriosplenography (CT AP–AS) in comparison to standard cross-sectional imaging and upper gastrointestinal endoscopy (UGE) in pediatric portal hypertension (PH) was analyzed. Patients with clinical signs of PH who underwent CT AP–AS in combination with additional contrast-enhanced magnetic resonance imaging (CE-MR) and/or contrast-enhanced computed tomography (CE-CT) were included. Two radiologists reviewed independently imaging regarding the capability to prove patency of (1) extrahepatic and intrahepatic main stem portal vein (PV), (2) intrahepatic PV system and (3) splenomesenteric venous axis. Imaging was reviewed for detection of abdominal varices and results were compared to UGE. Main venous supply of varices (PV and/or splenic vein system) and splenorenal shunting were evaluated. 47 imaging studies (20 CT AP-AS, 16 CE-MR, 11 CE-CT) and 12 UGE records of 20 patients were analyzed. CT AP–AS detected significantly more splenorenal shunts (p = 0.008) and allowed more confident characterization of the extra-/intrahepatic PV-system and splenomesenteric veins in comparison to CE-MR (p < 0.001). Extra- and intrahepatic PV-system were significantly more confidently assessed in CT AP–AS than in CE-CT (p = 0.008 and < 0.001 respectively). CT AP–AS was the only modality that detected supply of varices and additional gastric/duodenal varices. In this retrospective study CT AP–AS was superior to standard cross-sectional imaging concerning confident assessment of the venous portosplenomesenteric axis in pediatric patients. CT AP–AS detected additional varices, splenorenal shunting and supply of varices.

LOCAL DIAGNOSTIC REFERENCE LEVELS FOR PEDIATRIC RETROGRADE WEDGE PORTOGRAPHY INTERVENTIONAL PROCEDURES USING A DOSE MONITORING SOFTWARE AT A TRANSPLANTATION INSTITUTE

The aim of this work was to establish local diagnostic reference levels (DRLs) for retrograde wedge portography (RWP) performed on pediatric patients assessing the usefulness of radiation dose monitoring software in the establishing process. Between September 2016 and April 2020, 66 consecutive RWP were performed at a transplantation institute and were included in our study. Patients were divided in three groups according to age: n = 25 infants, n = 20 middle childhood and n = 21 early adolescence. The third quartile of both Air Kerma at the reference point (Ka,r) and air kerma-area product (PKA) were evaluated to establish local DRLs (lDRLs). In addition, to control high Ka,r levels during procedures, the software notified to operators if Ka,r exceeded the dose 'alert' threshold set at 2 Gy. lDRLs were established for all three groups using PKA and Ka,r: infant group: 5.6 Gy.cm 2 and 0.034 Gy; middle childhood: 6.4 Gy.cm2 and 0.018 Gy and early adolescence: 12.8 Gy.cm2 and 0.059 Gy. The dose threshold 'alert' was never encountered (alert quota: 0%). The dose monitoring system supports the feasibility of accurate and easier lDRLs' establishment.

Technical Aspects and Considerations of Meso-Rex Bypass Following Liver Transplantation With Left Lateral Segment Grafts: Case Report and Review of the Literature

In pediatric patients with extrahepatic portal vein obstruction and complications of portal hypertension, but with normal liver function, a meso-Rex bypass (MRB) connecting the superior mesenteric vein to the intrahepatic left portal is the favored surgical management. Pediatric patients with a history of a partial liver transplant (LT), especially living donors, are at greater risk for portal vein complications. Hence, an adequate knowledge of this technique and its additional challenges in the post-LT patient setting is crucial. We provide an overview of the available literature on technical aspects for an MRB post-LT. Preoperative considerations are highlighted, along with intraoperative considerations and postoperative management. Special attention is given to the even-more-demanding aspect of performing an MRB post-liver transplantation with a left lateral segment. Surgical alternatives are also discussed. In addition, we report here a unique case in which this surgical technique was performed on a complex pediatric patient with a history of a living-donor LT with a left lateral segment graft over a decade ago.

Sonographic Evaluation of a Unique Meso-Rex Shunt: A Case Study

Portal hypertension is a result of an increase in intrahepatic resistance in the main portal vein. The Meso-Rex shunt is used to bypass the obstructed portal vein and restore the venous flow into the liver. This procedure alleviates the need for a hepatic transplant. The Meso-Rex shunt has proven to be an effective treatment for extrahepatic portal vein obstruction, thus saving children from a complete transplant. There are variants to this bypass surgery, and sonography is commonly used to assess the condition pre- and postoperatively. In this case, the shunt was uniquely different from the typical Meso-Rex bypass surgery. Particular vasculature made it imperative for the sonographer to review the prior sonograms and review the chart information before preforming the examination. It should also be noted that sonographers must adapt the protocols to give the utmost treatment.

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.

Long-term Outcomes and Health Perceptions in Pediatric-onset Portal Hypertension Complicated by Varices

OBJECTIVES

Outcomes of pediatric-onset portal hypertension are poorly defined. We aimed to assess population-based long-term outcomes of pediatric-onset portal hypertension complicated by varices.

METHODS

All children with esophageal varices (n = 126) were identified from 14,144 single nationwide referral center endoscopy reports during 1987 to 2013, and followed up through national health care and death registers. A questionnaire was sent to survivors (n = 94) of whom 65 (69%) responded.

RESULTS

Nineteen underlying disorders included biliary atresia (35%), extrahepatic portal vein obstruction (35%), autosomal recessive polycystic kidney disease (7%), and other disorders (23%). During median follow-up of 15.2 (range 0.5-43.1) years patients underwent median 9 (1-74) upper gastrointestinal endoscopies. Esophageal varices were first observed at a median age of 4.0 (0.3-18.2) years, 112 (89%) patients underwent median 6 (1-56) sclerotherapy/banding sessions, and 61 (48%) experienced median 2 (range 1-20) variceal bleeding episodes. Forty-eight surgical shunt procedures were performed to 41 (36%) patients and 38% underwent liver transplantation. Portal hypertensive biliopathy was diagnosed in 4 patients. Hepatopulmonary syndrome necessitated liver transplantation in 2 patients, hepatic encephalopathy in 2, and hepatorenal syndrome in 1. No patient died of variceal bleeding. Patient-reported perception of health on a scale of 1 to 10 was 9 (range 4-10), and 86% reported no current symptoms attributable to esophageal varices.

CONCLUSIONS

Pediatric-onset portal hypertension is a heterogeneous disease with significant long-term morbidity, requiring multimodal approach with considerable resources and continuation of follow-up in adulthood. Although mortality to variceal bleeding was avoided, bleeding episodes recurred also in adulthood, while patient-reported health of long-term survivors was encouraging.

Effects of Rex-bypass shunt on the cavernous transformation of the portal vein in children: evaluation by the color Doppler ultrasonography

BACKGROUND

The study was to investigate the role of color Doppler ultrasonography in the evaluation of the effect of Rex-bypass shunt on the cavernous transformation of the portal vein (CTPV) in children.

METHODS

Fifty children with symptomatic extrahepatic portal hypertension who received Rex-bypass shunt were retrospectively reviewed, and they were diagnosed with CTPV by ultrasonography. The clinical characteristics were analyzed before and after operation.

RESULTS

Forty-five patients received color Doppler ultrasonography at 6 months after surgery, and good patency in the bypass vessels was displayed. The platelet count significantly increased (P < 0.001) and the esophagogastric varices were improved significantly (p < 0.001). The patency of bypass vessels on color Doppler ultrasonography was consistent with the changes in the platelet count and the degree of esophagogastric varices on gastroscopy before and after operation. The diameter of bypass vessels at 6 months was slightly larger than that at 7 days after operation, and there was no significant difference in blood flow velocity between two time points (P = 0.507).

CONCLUSIONS

Color Doppler ultrasonography can display the patency, diameter, and flow velocity of bypass vessels. It plays an important role in evaluating the effect of Rex-bypass shunt on the CTPV.