Spectrum of hepatofugal collateral pathways in portal hypertension: an illustrated radiological review

The Portal Vein: A Comprehensive Review

Radiologists are familiar with the appearances of a normal portal vein; variations in its anatomy are commonplace and require careful consideration due to the implications for surgery. These alterations in portal vein anatomy have characteristic appearances that are clearly depicted on CT, MR, and US images. Similarly, there are numerous congenital and acquired disorders of the portal vein that are deleterious to its function and can be diagnosed by using imaging alone. Some of these conditions have subtle imaging features, and some are conspicuous at imaging but poorly understood or underrecognized. The authors examine imaging appearances of the portal vein, first by outlining the classic and variant anatomy and then by describing each of the disorders that impact portal vein function. The imaging appearances of portal vein abnormalities discussed in this review include (a) occlusion from and differentiation between bland thrombus and tumor in vein and the changes associated with resultant hepatic artery buffer response changes, cavernous transformation of the portal vein, and portal biliopathy; (b) ascending thrombophlebitis of the portal vein (pylephlebitis); (c) portal hypertension and its causes and sequelae; (d) the newly described disease entity portosinusoidal vascular disorder; and (e) intra- and extrahepatic shunts of the portal system, both congenital and acquired (including Abernethy malformations), and the associated risks. Current understanding of the pathophysiologic processes of each of these disorders is considered to aid the approach to reporting. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

To evaluate the prevalence of spontaneous portosystemic shunts in decompensated cirrhosis patients and its prognostic significance

INTRODUCTION

Spontaneous portosystemic shunts (SPSS) are frequent in liver cirrhosis and their prevalence increases as liver function deteriorates, probably as a consequence of worsening portal hypertension, but without achieving an effective protection against cirrhosis complications. This study was conducted to detect the prevalence of portosystemic shunts in liver cirrhosis patients and analyze its prognostic role.

METHOD

We conducted a prospective observational study, where 92 patients with decompensated cirrhosis were evaluated based on history, physical examination, biochemical tests and abdominal computed tomography (CT) angiography findings. A follow-up was done after six months for the development of cirrhosis-related complications.

RESULTS

Of the 92 cirrhotic patients, 57.6% had SPSS (large SPSS + small SPSS) detected by multi-detector computed tomographic angiography. Overall, we found large SPSS in 24 (26.1%) patients, small SPSS in 29 (31.5%) patients and no shunt in 39 (42.4%) patients. Among the shunts, the splenorenal shunt is the most frequent type (25, 27.2%) followed by the paraumbilical shunt (20.7%). Previous decompensating events, including hepatic encephalopathy, ascites, spontaneous bacterial peritonitis and gastrointestinal bleed, were experienced more frequently by the large SPSS group followed by the small SPSS and without SPSS groups. Regarding follow-up, decompensating episodes of hepatic encephalopathy developed more frequently in patients with large SPSS (41.7%) than in patients with small SPSS (24.1%) followed by patients without SPSS (12.8%).

CONCLUSION

In summary, all cirrhotic patients should be studied with radiological imaging to detect the presence of portosystemic shunts. In several cases, patients with large SPSS had a more impaired liver function and more frequent complications of portal hypertension. So, these patients would probably benefit from a closer surveillance and more intensive therapy.

Varicocele Secondary to Splenic Vein Compression by Intragastric Balloon

Intragastric balloons (IGBs) are commonly used for weight loss by mechanically distending the stomach. We present a case of a 35-year-old man who developed a left-sided varicocele 1 week after IGB insertion. Imaging revealed splenic vein compression and possible thrombosis. Urgent removal of the balloon was performed. After 1 week from removal, the patient showed significant improvement, with complete splenic vein recanalization. This case highlights the importance of early recognition of a rare complication of IGBs to avoid severe outcomes. To our knowledge, this is the first reported case linking IGBs to splenic vein compression and varicocele.

Esophageal and stomach varices: physiological and anatomical features of formation

Esophageal and stomach varices: physiological and anatomical features of formation

Ectopic Vaginal Varices With Hemorrhage After Hysterectomy

Vaginal and uterine varices are well documented in pregnancy, although development of vaginal varices in patients with portal hypertension occurs in an exceptionally rare subset. Only 12 cases are reported in the literature; all but 3 of these cases involved patients with a history of hysterectomy, with 1 of the remaining 2 exhibiting partial obliteration of the uterine plexus due to radiation therapy for cervical cancer. We present a case of recurrent vaginal variceal bleeding in a patient with a history of hysterectomy, initially managed with vaginal tamponade and ultimately requiring definitive treatment with transjugular intrahepatic portosystemic shunt insertion.

Computed Tomography Images of Spontaneous Portosystemic Shunt in Liver Cirrhosis

Spontaneous portosystemic shunt (SPSS) refers to collateral vessels that communicate between the portal vein system and systemic circulation. SPSS mainly includes esophageal varices, gastric varices, left gastric vein, recanalized paraumbilical vein, abdominal wall varices, and spontaneous splenorenal shunt. SPSS contributes to the development of hepatic encephalopathy caused by portal vein inflow bypassing and carries a higher risk of death in liver cirrhosis. Abdominal contrast-enhanced computed tomography is a major imaging approach to establish a diagnosis of SPSS and evaluate its location and feature. This review primarily describes the main contrast-enhanced CT features of SPSS in liver cirrhosis.

Friend or Foe? Spontaneous Portosystemic Shunts in Cirrhosis-Current Understanding and Future Prospects

Portal hypertension (PHT) in cirrhosis results from increased resistance to splanchnic blood flow secondary to parenchymal and vascular changes within the liver. In an attempt to counteract the increased portal pressure, two mechanisms simultaneously occur: splanchnic vasodilatation and formation of spontaneous portosystemic shunts (SPSS). Long considered to be a compensatory mechanism to decompress the portal venous system, it is now well established that SPSS are not only inefficient in decreasing the portal pressure but also contribute to reduced hepatocyte perfusion and increased splanchnic blood flow and resistance, associated with worsening PHT. Recent studies have described a high prevalence of SPSS in cirrhosis patients, increasing with liver dysfunction, and observed an association between the presence of SPSS and worse clinical outcomes. In cirrhosis patients with preserved liver functions, the presence of SPSS independently increases the risk of hepatic encephalopathy, variceal bleeding, and ascites, and reduces transplant-free survival. Moreover, the presence of SPSS in patients undergoing transjugular intrahepatic portosystemic shunting and liver transplant has been shown to variably affect the postprocedural outcome. This article provides an overview of the current understanding of the role of SPSS in the natural history of liver cirrhosis and their status as a therapeutic target and an imaging biomarker to identify patients at higher risk of developing complications of PHT.

Nomogram for hepatic venous pressure gradient in patients with cirrhosis

OBJECTIVE

The hepatic venous pressure gradient (HVPG) plays an important role in the treatment and prognosis of patients with cirrhosis. Our study aimed to develop and validate a nomogram for an HVPG >12 mmHg.

METHODS

A retrospective study was performed to create a nomogram for an HVPG >12 mmHg in a training cohort that was validated in another cohort. The discriminatory ability and calibration of the nomogram were tested using the C-statistic, area under the receiver operating characteristic curve (AUROC) and calibration plots.

RESULTS

The nomogram was based on portosystemic shunts identified on computed tomography images, the etiology of cirrhosis and the Child-Pugh grade. These parameters were significantly associated with an HVPG >12 mmHg (P < 0.05 for both the training and validation cohorts). In the training cohort, the model showed good discrimination (C-statistic, AUROC, and R² of 0.71, 0.71 and 0.13, respectively) and good calibration. The total cutoff value was 112 and the sensitivity and specificity were 57.1% and 77.6%, respectively. The application of the nomogram in the validation cohort still yielded good discrimination (C-statistic 0.75 [95% confidence interval 0.61-0.89], AUROC 0.75, and R² 0.16) and good calibration.

CONCLUSIONS

This nomogram is a convenient tool for predicting an HVPG >12 mmHg in patients with cirrhosis and can help clinicians quickly identify patients with decompensated cirrhosis.

Cauda equina syndrome secondary to portal vein thrombosis: case report of favorable outcome with conservative treatment

Epidural varicosis is a rare though well-known cause of cauda equina syndrome (CES). Although inferior vena cava (IVC) obstruction is the most common finding in such cases, portal vein hypertension can lead to epidural venous plexus engorgement by means of lumbar portocaval shunt activation.

A 40-year-old woman presented with right-sided sciatica, which progressed to right foot drop and a 3-day history of vesical tenesmus and fecal retention. She was initially diagnosed with L4–5 lumbar disc protrusion. However, contrast-enhanced lumbar MRI scan showed the presence of epidural varices in the L3–S1 tract. Given the absence of vascular anomalies amenable to resection, etiological conservative treatment was addressed. Therefore, a complete diagnostic workup was performed and revealed deep vein thrombosis (DVT), pulmonary embolism, and portal vein thrombosis. Oral anticoagulant therapy was initiated and prompt resolution of CES was observed. To the authors’ knowledge, this is the first report of CES secondary to epidural varicosis in the setting of acute portal vein thrombosis and extrahepatic portal vein obstruction (EHPVO). In cases of epidural varicosis, conservative etiological treatment is the most appropriate choice as CES may be the epiphenomenon of underlying systemic pathophysiological processes.

Cauda equina syndrome secondary to portal vein thrombosis: case report of favorable outcome with conservative treatment

Epidural varicosis is a rare though well-known cause of cauda equina syndrome (CES). Although inferior vena cava (IVC) obstruction is the most common finding in such cases, portal vein hypertension can lead to epidural venous plexus engorgement by means of lumbar portocaval shunt activation.A 40-year-old woman presented with right-sided sciatica, which progressed to right foot drop and a 3-day history of vesical tenesmus and fecal retention. She was initially diagnosed with L4-5 lumbar disc protrusion. However, contrast-enhanced lumbar MRI scan showed the presence of epidural varices in the L3-S1 tract. Given the absence of vascular anomalies amenable to resection, etiological conservative treatment was addressed. Therefore, a complete diagnostic workup was performed and revealed deep vein thrombosis (DVT), pulmonary embolism, and portal vein thrombosis. Oral anticoagulant therapy was initiated and prompt resolution of CES was observed. To the authors' knowledge, this is the first report of CES secondary to epidural varicosis in the setting of acute portal vein thrombosis and extrahepatic portal vein obstruction (EHPVO). In cases of epidural varicosis, conservative etiological treatment is the most appropriate choice as CES may be the epiphenomenon of underlying systemic pathophysiological processes.

Beyond the scope and the glue: update on evaluation and management of gastric varices

Gastric varices are encountered less frequently than esophageal varices. Nonetheless, gastric variceal bleeding is more severe and associated with worse outcomes. Conventionally, gastric varices have been described based on the location and extent and endoscopic treatments offered based on these descriptions. With improved understanding of portal hypertension and the dynamic physiology of collateral circulation, gastric variceal classification has been refined to include inflow and outflow based hemodynamic pathways. These have led to an improvement in the management of gastric variceal disease through newer modalities of treatment such as endoscopic ultrasound-guided glue-coiling combination therapy and the emergence of highly effective endovascular treatments such as shunt and variceal complex embolization with or without transjugular intrahepatic portosystemic shunt (TIPS) placement in patients who are deemed ‘difficult’ to manage the traditional way. Furthermore, the decisions regarding TIPS and additional endovascular procedures in patients with gastric variceal bleeding have changed after the emergence of ‘portal hypertension theories’ of proximity, throughput, and recruitment. The hemodynamic classification, grounded on novel theories and its cognizance, can help in identifying patients at baseline, in whom conventional treatment could fail. In this exhaustive review, we discuss the conventional and hemodynamic diagnosis of gastric varices concerning new classifications; explore and illustrate new ‘portal hypertension theories’ of gastric variceal disease and corresponding management and shed light on current evidence-based treatments through a ‘new’ algorithmic approach, established on hemodynamic physiology of gastric varices.

Plug-Assisted Retrograde Transvenous Obliteration (PARTO): Anatomical Factors Determining Procedure Outcome

PURPOSE

To study various anatomical factors determining procedure success versus failure for plug-assisted retrograde transvenous obliteration (PARTO) of gastro-lieno-renal shunt.

MATERIALS AND METHODS

A retrospective review of 50 patients (M:F-37:13; mean age 58.4yrs) who were planned for PARTO of gastro-lieno-renal shunt from July 2017 to July 2019 was done. Anatomical factors [shunt diameter, shunt angle, shunt orientation, left renal vein (LRV) size/calibre and distance of shunt from renal vein-IVC confluence] were analysed on a pre-procedure CT. Statistical analysis of the data was done to assess the relationship between these factors and technical success/failure.

RESULTS

PARTO was successfully performed in 82% (n = 41). Analysis of anatomical factors showed that aneurysmal dilatation of the LRV, extreme acute/obtuse angulation and extreme antero-posterior orientation of the shunt in relation to the LRV was associated with higher probability of technical failure of PARTO. Minimum/maximum and entry point shunt diameter was not associated with procedure outcome. It was also noted that an increased distance of the shunt from the renal vein-IVC confluence favoured trans-jugular over trans-femoral venous access for PARTO.

CONCLUSION

Knowledge of various anatomical factors of gastro-lieno-renal shunt may help in deciding the access route for PARTO and may determine technical success/failure. Alternate methods like BRTO or coil-assisted obliteration (CARTO) or anterograde obliteration of the shunt via trans-hepatic/splenic route might be needed in such circumstances.

Spastic paraparesis associated with advanced liver cirrhosis: a condition obscure in terms of treatment and prognosis

Hepatic myelopathy or spastic paraparesis of liver disease is an insidious onset condition with pure motor spastic paraparesis without sensory, bladder or bowel involvement in patients with chronic liver disease, in which the neurological dysfunction cannot be explained by other causes. It is a rare, relentlessly progressive and mostly irreversible neurological complication resulting from portosystemic shunts occurring spontaneously, created surgically or due to 'functional shunting'. In some cases, no evidence of shunting is elicitable due to difficulty in locating the hidden collaterals. We report this rare case of a 33-year-old man with chronic liver disease presenting with spastic paraparesis after 11 months of resolution of an episode of hepatic encephalopathy.

The Azygos Vein From A to Z

Congenital and acquired abnormalities of the azygos vein can affect its size and position. Alteration of contrast material flow dynamics of the azygos vein on computed tomography can be an indication of superior vena cava obstruction. Recognition and accurate characterization of abnormalities of the azygos vein on imaging studies is critical to facilitate prompt diagnosis and direct workup when necessary. The main purpose of this article is to illustrate and describe the radiologic features of various congenital and acquired abnormalities affecting the azygos venous system.

Computed tomography evaluation of patent paraumbilical vein and its aneurysm in relation to other portosystemic collateral channels in patients with liver cirrhosis and portal hypertension

Purpose

The aim of the study was to evaluate the relationship between the diameter and aneurysmal dilatation of the paraumbilical vein (PUV) and the presence of portosystemic collateral shunts and their relationship with age and portal vein diameter.

Material and methods

The retrospective analysis, performed in the II Department of Radiology, Medical University Hospital in Warsaw, included 126 patients (77 males and 49 females) with patent umbilical vein and signs of portal hypertension due to liver cirrhosis. All patients underwent contrast enhanced abdominal CT. The average age was 54.7 ±12.98. We analysed the number and type of portosystemic collateral channels in respect of age, sex, presence of oesophageal varices, and the diameter of the paraumbilical vein and the portal vein.

Results

Our results disclosed statistically significant negative correlation between patient age and diameter of paraumbilical vein, number of portosystemic collateral channels and diameter of portal vein and positive correlation between diameter of paraumbilical vein and diameter of portal vein. A statistically significant difference in diameter of portal vein and number of collateral channels was found in groups with and without oesophageal varices. No significant difference in age and portal vein diameter was found in these groups.

Conclusions

Our study showed that younger patients with liver cirrhosis are characterised by wider paraumbilical veins and higher number of portosystemic collateral channels. The presence of oesophageal varices does not correlate with age, sex, diameter of paraumbilical vein, and number of collateral portosystemic channels.

Early TIPS failure in association with left mesenterico-gonadal spontaneous portosystemic venous shunt; a case report

Transjugular intrahepatic portosystemic shunt (TIPS) periprocedural thrombosis rates have fallen significantly since the introduction of polytetrafluoroethylene-covered stent grafts. We present a case of a cirrhotic patient with portal hypertension presenting with early TIPS thrombosis in association with an underlying competing spontaneous left mesenterico-gonadal venous shunt, an uncommon variant of spontaneous portal systemic shunt (SPSS). The patient presented with bleeding distal duodenal varices refractory to endovascular therapy, and although a successful TIPS procedure was performed for this indication, early thrombosis was determined by follow-up abdominopelvic computed tomographic angiography (CTA) scan. Despite undergoing a standard TIPS revision procedure, blood flow through the TIPS remained hepatofugal. During a TIPS revision, portal vein angiography revealed competing large inferior mesenteric vein (IMV) varices shunting into the left renal vein via the left gonadal vein. The initial abdominal CTA was later reviewed by a non-invasive cardiovascular radiologist, and the presence of the competing left mesenterico-gonadal shunt was retrospectively identified. Radiologists interpreting CTA exams should be aware of SPSS generally and mesenterico-gonadal shunts specifically. Pre-procedural knowledge of underlying SPSS can affect post procedural outcomes and should be emphasized in the final CTA report.

Rectal varices due to chronic inferior mesenteric vein thrombosis caused by external compression in a large hiatus hernia containing the pancreas

A 79-year-old woman presented with a large fresh rectal bleed. Computed tomography revealed that she had a large type IV hiatus hernia, which contained the stomach and pancreas. Compression of the inferior mesenteric vein and splenic vein had led to thrombosis within these vessels and retrograde flow within the inferior mesenteric vein. This had led to the formation of portosystemic rectal varices. Ectopic varices occasionally form in the rectum, often in the context of liver cirrhosis. At the time of writing, ours is the first reported case of portosystemic rectal varices formulated in response to obstruction of vessels within a hiatus hernia.

Portal systemic shunt between the hepatic portal vein and right renal vein in a patient with multifocal hepatocellular carcinoma: Case report

Portal hypertension is a clinical syndrome characterized by the development of collateral circulation and portosystemic shunts, as well as ascites and hepatic encephalopathy. We present the case of a large portosystemic shunt between the hepatic portal vein and aneurysmal right renal vein in a cirrhotic 64-year-old man with thrombosis of the portal vein and hepatocellular carcinoma. This is a very rare clinical manifestation which, to our knowledge, has been described only once previously in the literature. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:524-527, 2017.

Prevalence and Clinical Characteristics of Spontaneous Splenorenal Shunt in Liver Cirrhosis: A Retrospective Observational Study Based on Contrast-Enhanced Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) Scans

BACKGROUND This is a retrospective observational study evaluating the prevalence and clinical characteristics of spontaneous splenorenal shunt in liver cirrhosis. MATERIAL AND METHODS We included a total of 105 cirrhotic patients who were admitted to our hospital between June 2012 and December 2013 and underwent contrast-enhanced CT and/or MRI scans at admissions. Spontaneous splenorenal shunt was identified. Clinical and laboratory data were compared between cirrhotic patients with and without spontaneous splenorenal shunt. RESULTS The prevalence of spontaneous splenorenal shunt was 10.5% (11/105). The prevalence of hepatic encephalopathy was higher in patients with spontaneous splenorenal shunt than in those without spontaneous splenorenal shunt (18.2% vs. 4.3%, p=0.062), but the difference between them was not statistically significant. The prevalence of acute upper-gastrointestinal bleeding was lower in patients with spontaneous splenorenal shunt than in those without spontaneous splenorenal shunt (0% vs. 18.1%, p=0.205), but the difference between them was not statistically significant. Patients with spontaneous splenorenal shunt had significantly higher Child-Pugh scores (9.50±1.65 vs. 7.43±2.02, p=0.002) and MELD scores (11.26±7.29 vs. 5.67±6.83, p=0.017) than those without spontaneous splenorenal shunt. In-hospital mortality was similar between them (0% vs. 4.3%, p=1.000). CONCLUSIONS Spontaneous splenorenal shunt might be associated with worse liver function in liver cirrhosis, but not with in-hospital mortality.

Utility of cone-beam computed tomography in the assessment of the porto-spleno-mesenteric venous system

The common diagnostic tools available to evaluate the porto-spleno-mesenteric venous (PSMV) system provide either good hemodynamic information with limited morphological details [e.g., ultrasonography (US)] or excellent tomographic display of the anatomy with limited information about flow patterns [e.g., multidetector computed tomography (MDCT) and magnetic resonance imaging]. Although catheter-directed selective digital subtraction angiography (DSA) can provide excellent information about flow at a high temporal resolution and can generate images at a high spatial resolution, this technique is often limited by a lack of cross-sectional detail. In the assessment of the PSMV system, DSA is also limited by dilution of contrast and motion artefacts. Combining venous phase cone-beam computed tomography (CBCT) with DSA can generate high-quality tomographic data, which allows detailed evaluation of venous tributaries and flow patterns within the splenic, superior mesenteric, and inferior mesenteric venous systems individually. This enables clinicians to better understand the impact of nonobstructive resistance to flow (e.g., as in patients with cirrhosis) and obstructive resistance to flow (e.g., as in patients with thrombosis) within each system and plan treatment accordingly. In this review, we discuss the limitations of common diagnostic methods and the role venous CBCT in combination with DSA can play in assessing the PSMV system.

Restructuring of the vascular bed in response to hemodynamic disturbances in portal hypertension

In recent years, defined progress has been made in understanding the mechanisms of hemodynamic disturbances occurring in liver cirrhosis, which are based on portal hypertension. In addition to pathophysiological disorders related to endothelial dysfunction, it was revealed: There is the restructuring of the vasculature, which includes vascular remodeling and angiogenesis. In spite of the fact that these changes are the compensatory-adaptive response to the deteriorating conditions of blood circulation, taken together, they contribute to the development and progression of portal hypertension causing severe complications such as bleeding from esophageal varices. Disruption of systemic and organ hemodynamics and the formation of portosystemic collaterals in portal hypertension commence with neovascularization and splanchnic vasodilation due to the hypoxia of the small intestine mucosa. In this regard, the goal of comprehensive treatment may be to influence on the chemokines, proinflammatory cytokines, and angiogenic factors (vascular endothelial growth factor, placental growth factor, platelet-derived growth factor and others) that lead to the development of these disorders. This review is to describe the mechanisms of restructuring of the vascular bed in response to hemodynamic disturbances in portal hypertension. Development of pathogenetic methods, which allow correcting portal hypertension, will improve the efficiency of conservative therapy aimed at prevention and treatment of its inherent complications.

A Comprehensive Review of Portosystemic Collaterals in Cirrhosis: Historical Aspects, Anatomy, and Classifications

Portosystemic collateral formation in cirrhosis plays an important part in events that define the natural history in affected patients. A detailed understanding of collateral anatomy and hemodynamics in cirrhotics is essential to envisage diagnosis, management, and outcomes of portal hypertension. In this review, we provide detailed insights into the historical, anatomical, and hemodynamic aspects to portal hypertension and collateral pathways in cirrhosis with emphasis on the various classification systems.