Chronic portal vein thrombosis: transcapsular hepatic collateral vessels and communicating ectopic varices

Ectopic varices: anatomical features for surgeons and interventional radiologists

Ectopic varices are defined as dilated portosystemic collateral veins located in unusual sites, other than the gastroesophageal region. They develop secondary to portal hypertension, surgical procedures, anomalies in venous outflow, or abdominal vascular thrombosis and may be familial. Ectopic varices represent a clinical challenge because they are difficult to localize. Missing or misinterpreting these lesions can have serious consequences, and treatment options are unclear. Ectopic varices may be detected during panendoscopy, enteroscopy, endoscopic ultrasound, wireless capsule endoscopy, diagnostic angiography, multislice helical computed tomography, magnetic resonance angiography, color Doppler flow imaging, laparotomy, laparoscopy and occasionally during autopsy. They can be an important cause of bleeding and hepatic encephalopathy, so radiologists must effectively identify them to assist in making therapeutic decisions. Knowledge of the anatomy and course of these unusual portosystemic collaterals is also important for interventional radiologists and surgeons as it helps avoid inadvertent vascular damage during invasive procedures. In this article, we explore the parts of the gastrointestinal tract and organs that may be involved in ectopic varices. Literature search was conducted in the MedLine database on the PubMed platform.

Unusual venous collateral pathways allow for reperfusion of the intrahepatic portal venous system in children with portal vein thrombosis after split liver transplantation: Clinical relevance and management implications

PVT is the most frequent vascular complication after LT in small children, and a higher incidence has been observed in those transplanted for biliary atresia or with a LLSG. Thrombosis of the PV causes extrahepatic portal hypertension and is associated with splenomegaly and the development of venous neo-collaterals, including gastro-oesophageal varices and splenorenal shunts. It has also been incidentally suggested in the literature that patients who have had a Roux-en-Y loop for a biliary reconstruction may present with a cavernomatous transformation of the distal portion of the loop. In this study, 13 children with CEPH caused by thrombosis of the PV after LT were analysed. The study evidenced the development of two types of hepatopetal venous networks: (a) a large cavernoma along the Roux loop and around the biliary anastomosis, and (b) a network of neo-collaterals in the gastro-duodeno-pancreatic area that connected to the intrahepatic portal branches directly through the liver capsule. These hepatopetal venous networks between the venous system of the surrounding organs or the omentum and the intrahepatic portal branches can be identified by radiologists. The relevance for the transplanting physician and the transplant surgeon is discussed.

Recurrent Ectopic Variceal Bleed After Pancreas Transplantation With No Portal Hypertension: Case Report and Outcomes of Endovascular Onyx Embolization

A 57-year-old male presented with intermittent gastrointestinal bleeding (GIB) 1 year after a successful simultaneous pancreas and kidney transplant. No source could be found after 5 tagged red blood cell studies, 3 computed tomographies (CTs), 7 endoscopies, and 4 catheter angiograms. Review of CTs showed pathologically enlarged superior mesenteric vein branches near a jejunal segment near pancreas graft. Transhepatic superior mesenteric venogram showed varicosities near jejunum, which were obliterated with ethylene vinyl alcohol (Onyx). Follow-up CTs confirmed complete obliteration, but he had more GIBs and eventually underwent native jejunal and donor duodenal resection. He has remained GIB-free for 12 months.

Pediatric Liver Transplant: Techniques and Complications

Liver transplant is considered to be the last-resort treatment approach for pediatric patients with end-stage liver disease. Despite the remarkable advance in survival rates, liver transplant remains an intricate surgery with significant morbidity and mortality. Early diagnosis of complications is crucial for patient survival but is challenging given the lack of specificity in clinical presentation. Knowledge of the liver and vascular anatomy of the donor and the recipient or recipients before surgery is also important to avoid complications. In this framework, radiologists play a pivotal role on the multidisciplinary team in both pre- and postoperative scenarios by providing a road map to guide the surgery and by assisting in diagnosis of complications. The most common complications after liver transplant are (a) vascular, including the hepatic artery, portal vein, hepatic veins, and inferior vena cava; (b) biliary; (c) parenchymal; (d) perihepatic; and (e) neoplastic. The authors review surgical techniques, the role of each imaging modality, normal posttransplant imaging features, types of complications after liver transplant, and information required in the radiology report that is critical to patient care. They present an algorithm for an imaging approach for pediatric patients after liver transplant and describe key points that should be included in radiologic reports in the pre- and postoperative settings. Online supplemental material is available for this article. ^©RSNA, 2017.

Imaging Diagnosis of Splanchnic Venous Thrombosis

Splanchnic vein thrombosis (SVT) is a broad term that includes Budd-Chiari syndrome and occlusion of veins that constitute the portal venous system. Due to the common risk factors involved in the pathogenesis of these clinically distinct disorders, concurrent involvement of two different regions is quite common. In acute and subacute SVT, the symptoms may overlap with a variety of other abdominal emergencies while in chronic SVT, the extent of portal hypertension and its attendant complications determine the clinical course. As a result, clinical diagnosis is often difficult and is frequently reliant on imaging. Tremendous improvements in vascular imaging in recent years have ensured that this once rare entity is being increasingly detected. Treatment of acute SVT requires immediate anticoagulation. Transcatheter thrombolysis or transjugular intrahepatic portosystemic shunt is used in the event of clinical deterioration. In cases with peritonitis, immediate laparotomy and bowel resection may be required for irreversible bowel ischemia. In chronic SVT, the underlying cause should be identified and treated. The imaging manifestations of the clinical syndromes resulting from SVT are comprehensively discussed here along with a brief review of the relevant clinical features and therapeutic approach.

Pancreatic cancer and thromboembolic disease, 150 years after Trousseau

The connection between pancreatic cancer and venous thrombosis has been discussed for almost 150 years. The exact pathophysiological mechanisms are still partly understood, but it is known that pancreatic cancer induces a prothrombotic and hypercoagulable state and genetic events involved in neoplastic transformation (e.g., KRAS, c-MET, p53), procoagulant factors [e.g., tissue factor (TF), platelet factor 4 (PF4), plasminogen activator inhibitor type 1 (PAI-1)], mucin production (e.g., through activation of P- and L-selectin) and pro-inflammatory factors [e.g., cytokines, cyclooxygenase-2 (COX-2)] may be implicated. Also pancreatitis, both acute and chronic, is associated with increased risk of venous thrombosis, but in this circumstance a direct inflammatory process may be more important. This article discusses the incidence, treatment and outcome of venous thromboembolism (VTE) complicating pancreatic disease, with special emphasis on new knowledge obtained during the last fifteen years.

Protein C deficiency related obscure gastrointestinal bleeding treated by enteroscopy and anticoagulant therapy

Obscure gastrointestinal bleeding is an uncommonly encountered and difficult-to-treat clinical problem in gastroenterology, but advancements in endoscopic and radiologic imaging modalities allow for greater accuracy in diagnosing obscure gastrointestinal bleeding. Ectopic varices account for less than 5% of all variceal bleeding cases, and jejunal variceal bleeding due to extrahepatic portal hypertension is rare. We present a 47-year-old man suffering from obscure gastrointestinal bleeding. Computed tomography of the abdomen revealed multiple vascular tufts around the proximal jejunum but no evidence of cirrhosis, and a visible hypodense filling defect suggestive of thrombus was visible in the superior mesenteric vein. Enteroscopy revealed several serpiginous varices in the proximal jejunum. Serologic data disclosed protein C deficiency (33.6%). The patient was successfully treated by therapeutic balloon-assisted enteroscopy and long-term anticoagulant therapy, which is normally contraindicated in patients with gastrointestinal bleeding. Diagnostic modalities for obscure gastrointestinal bleeding, such as capsule endoscopy, computed tomography enterography, magnetic resonance enterography, and enteroscopy, were also reviewed in this article.

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.

Management of portal hypertension in children with portal vein thrombosis

Portal vein thrombosis (PVT) is a common cause of portal hypertension in children. Predisposing conditions for PVT are obscure in more than half of the cases. Variceal bleeding and splenomegaly are the most frequent initial manifestations. Radiologic imaging studies are the mainstay for diagnosis. Treatment includes pharmacologic, endoscopic, and surgical modalities. β-Adrenergic blockers are not routinely used in children because of unproven efficacy and significant adverse effects. Endoscopic methods, such as sclerotherapy and endoscopic variceal ligation (EVL), are highly effective in the treatment of acute variceal bleeding and eradication of varices. EVL is the treatment of choice because of minimal complications and the need for few endoscopic sessions. EVL facilitates portal decompression either by the formation of collateral vessels or by surgical portosystemic shunting, when vessels grow to the proper diameter for anastomosis. Surgical portosystemic shunts are reserved for refractory cases because of significant complications and technical difficulties. Transjugular portosystemic shunts have an emerging role in the management of portal hypertension caused by PVT. PVT may occur in the posttransplant setting, but optimal management is not defined yet.

CT findings of afferent loop varices after bilioenteric anastomosis in patients with malignant disease

OBJECTIVE

The purpose of this study was to determine the prevalence and CT findings of afferent jejunal loop varices after bilioenteric anastomosis in patients with malignancy.

MATERIALS AND METHODS

The study included 99 patients who underwent bilioenteric anastomosis for malignancy and follow-up CT examinations. Two abdominal radiologists reviewed CT images for the presence of afferent loop varices. They also assessed for the presence of extrahepatic portal occlusion or stenosis, other collateral vessels, ascites, splenomegaly, and recurrent tumor. Clinical data regarding age, sex, and histories of pancreaticoduodenectomy and surgery on the portal vein, radiation therapy, and postoperative gastrointestinal bleeding were collected. Univariate and multivariate analyses were performed to discern significant factors associated with afferent loop varices. Cumulative incidence was estimated with the Kaplan-Meier method.

RESULTS

Afferent loop varices were found in 22 of the 99 patients (22.2%), and the 48-month cumulative incidence of afferent loop varices was 28.0%. Three of the 22 patients (13.6%) eventually experienced gastrointestinal bleeding. Obstruction in the extrahepatic portal system was the only feature that exhibited a significant difference in multivariate analysis (relative risk, 71.4; 95% CI, 7.4-1000).

CONCLUSION

Afferent loop varices detected after bilioenteric anastomosis on CT images had a prevalence of 22.2% and can result in gastrointestinal bleeding. The presence of obstruction in the extrahepatic portal system was significantly associated with afferent loop varices.

Collateral pathways in portal hypertension

Presence of portosystemic collateral veins (PSCV) is common in portal hypertension due to cirrhosis. Physiologically, normal portosystemic anastomoses exist which exhibit hepatofugal flow. With the development of portal hypertension, transmission of backpressure leads to increased flow in these patent normal portosystemic anastomoses. In extrahepatic portal vein obstruction collateral circulation develops in a hepatopetal direction and portoportal pathways are frequently found. The objective of this review is to illustrate the various PSCV and portoportal collateral vein pathways pertinent to portal hypertension in liver cirrhosis and EHPVO.