Portal and Mesenteric Venous Thrombosis.

Review Portal and Mesenteric Venous Thrombosis Sudha Kodali, M.D., M.S.P.H.,* and Ashwani K. Singal, M.D., M.S., F.A.C.G., F.A.A.S.L.D.† PREVALENCE AND ETIOLOGY The main portal vein (PV) is formed with superior mesenteric and splenic veins joining at the posterior aspect of pancreas; it carries blood from the gastrointestinal tract to contribute 70% of the hepatic blood supply. Similar to venous thrombosis at any other site, PV thrombosis (PVT) and/or mesenteric vein thrombosis (MVT) can be caused by vascular endothelial injury, sluggish blood flow, or underlying thrombophilia (Table 1).1-4 Cirrhosis is the underlying etiology in about 22% to 28% of cases based on a large population-based autopsy study.5 Among patients with cirrhosis, the prevalence rate of PVT varies depending on the severity of the liver disease (1% in compensated cirrhosis to 25% among patients listed for liver transplantation [LT]),3,5 modality used for diagnosis, etiology of cirrhosis (more common among patients with nonalcoholic steatohepatitis),6 and length of follow-up of patients with cirrhosis. In a recent longitudinal study, the cumulative incidence rate of PVT was 4.6%, 8.2%, and 10.7% at 1, 3, and 5 years, respectively.4 PVT may be acute or chronic, partial or complete, occlusive or nonocclusive, when all etiologies for PVT are considered. Further, among patients with cirrhosis, this could be caused by bland or tumor thrombus. CLINICAL FEATURES Abdominal pain is the most common symptom of PVT or MVT, and abdominal examination is relatively benign compared with the severity of pain. Other nonspecific symptoms, such as nausea, vomiting, and diarrhea, can Abbreviations: aPTT, activated partial thromboplastin time; BB, beta blocker; EGD, esophagogastroduodenoscopy; EVL, endoscopic variceal ligation; INR, international normalized ratio; LMWH, low molecular weight heparin; LT, liver transplantation; MR, magnetic resonance; MVT, mesenteric vein thrombosis; PV, portal vein; PVT, portal vein thrombosis; TIPS, transjugular intrahepatic portosystemic shunt. From the * Sherrie and Alan Conover Center for Liver Disease and Transplant Medicine, Methodist Hospital, Houston, TX; and † Division of Gastroenterology and Hepatology, University of South Dakota, Avera McKennan University Health Center and Transplant Institute, Sioux Falls, SD. Potential conflict of interest: A.K.S. consults for Guidepoint, advises Gilead, is on the speakers’ bureau for the Medical Education Speakers Network, and receives royalties from Up-To-Date. Received December 3, 2019; accepted January 11, 2020. View this article online at wileyonlinelibrary.com © 2020 by the American Association for the Study of Liver Diseases | Clinical Liver Disease, VOL 16, NO 4, OCTOBER 2020 142   An Official Learning Resource of AASLD Review TABLE 1. ETIOLOGY OF PVT AND MVT A. Thrombophilia • Intra-abdominal malignancy • Myeloproliferative neoplasm • Inherited thrombophilia • Pregnancy • Oral contraceptive use B. Local intra-abdominal trauma or injury to vessel wall • Acute intra-abdominal process: pancreatitis, inflammatory bowel disease, diverticulitis, cholecystitis, appendicitis • Intra-abdominal surgery: splenectomy, colectomy, cholecystectomy, splenectomy, portosystemic shunting • Abdominal trauma C. Sluggish blood flow • Cirrhosis • Congestive heart failure occur because of involvement of mesenteric veins. Fever can occur in 10% to 15% of cases because of an underlying inflammatory intra-abdominal process, pylephlebitis with liver abscess, or intestinal infarction from MVT.1 Among patients with cirrhosis, PVT can be asymptomatic or patients may present with abdominal pain and/or with worsening of liver disease. It is important to exclude tumor thrombus when a new-onset PVT is encountered in patients with cirrhosis. Chronic PVT often presents with features of portal hypertension. In approximately 1% of patients, chronic PVT can result in biliary cholangiopathy because of peribiliary vascular collaterals compressing on extrahepatic bile ducts, which manifests with features of cholangitis.7 DIAGNOSIS Routine hematological and biochemical assessment including hypercoagulable workup is recommended among patients with PVT and/or MVT. For specific diagnosis of PVT, Doppler ultrasound examination is recommended as the initial screening test. Its advantages are high negative predictive value of 98%, inexpensive cost, and lack of radiation exposure. However, the technique is operator dependent, and the finding of a filling defect in the PV has a positive predictive value of only 86% to 97%.8 Contrastenhanced computed tomography or magnetic resonance (MR) scan is recommended before starting specific treatment with anticoagulation to confirm the diagnosis, differentiate bland versus tumor thrombus, and assess the mesenteric vasculature (MVT, bowel ischemia, gangrene, and bowel perforation). An intraluminal filling defect on computed tomography or MR scan is 90% accurate for diagnosis of MVT, which increases to 100% with use of the multidetector technique.8 Portosystemic collaterals Portal and Mesenteric Venous Thrombosis Kodali and Singal and cavernoma with serpiginous vessels replacing the PV suggest diagnosis of chronic PVT. MR cholangiography coupled with MR portography is an accurate noninvasive modality to diagnose biliary cholangiopathy among patients with chronic PVT. Thrombophilia workup (Table 2) is recommended for patients without cirrhosis if there is no obvious etiology (Table 1).1 Among patients with cirrhosis, thrombophilia workup should be considered for patients with a family history of thrombosis and if the thrombosis involves an unusual site, such as hepatic veins.1 TREATMENT Anticoagulation is recommended to be initiated as soon as possible for the management of acute thrombosis, except in patients suspected to have bowel gangrene or perforation, which require urgent surgical intervention. Thrombophilia workup, if indicated, should be obtained prior to starting anticoagulation. Among patients with acute MVT, anticoagulation improves recanalization rates, prevents bowel ischemia or need for surgical intervention, and improves survival.1 In one study, anticoagulation resulted in complete recanalization in 44% and partial recanalization in 56% of patients.9 Anticoagulation for chronic PVT is used among patients with cirrhosis if there is underlying thrombophilia or with extension to mesenteric veins with features of bowel ischemia. In one retrospective study on 60 patients with chronic thrombosis of PVs or superior mesenteric veins (39 with variceal bleeding), 18 with thrombophilia (9 with variceal bleeding) received anticoagulation, with recanalization of veins in 3 patients, whereas none of the patients who were not anticoagulated TABLE 2. WORKUP FOR THROMBOPHILIA OR HYPER COAGULABLE STATE Thrombophilia Workup Myeloproliferative disease Paroxysmal nocturnal hemoglobinuria Factor V Leiden Antiphospholipid syndrome Hype (...truncated)