1 Portal Vein Thrombosis Sophia A. Virani, HMS III Gillian Lieberman, MD Beth Israel Deaconess Medical Center Department of Radiology March 2009
2 Agenda Introduce index patient Discuss portal vein thrombosis (PVT) Etiology Menu of radiologic tests Complications Review hepatic anatomy and vasculature Companion Cases Review various treatment options
3 Let s s meet our patient
4 Ms. S: Initial presentation Ms. S is a 61 year old woman with ulcerative colitis and primary biliary cirrhosis (PBC) who was transferred from an outside hospital with worsening abdominal pain, bloody diarrhea and ascites Her ulcerative colitis had become steroid-unresponsive during the weeks prior to admission She has had PBC for ten years and her illness has been complicated by ascites and hepatic encephalopathy A review of her outside hospital CT showed a possible portal vein thrombus
5 Portal Vein Thrombus: Overview Rare event but can have serious clinical consequences Types Acute or chronic Bland or malignant Presentation Often subtle or asymptomatic Symptoms are often those of primary illness GI bleeding, abdominal pain, varices, ascites and splenomegaly In symptomatic patients, variceal bleeding is the most common presentation Complications Portal hypertension from increased pressure to portal vein obstruction Thrombus can spread to splanchnic veins and potentially cause mesenteric ischemia, which is a surgical emergency High clinical suspicion and effective interpretation of radiologic findings are key to making the diagnosis of portal vein thrombus
6 Etiology of Portal Vein Thrombus Cirrhosis 25% of patients with PVT have cirrhosis 1% of patients with cirrhosis develop PVT Likelihood of developing thrombus is associated with severity of disease Stasis of flow in portal system predisposes to clot formation Deficiency of protein C, protein S and antithrombin III lead to a hypercoagulable state Malignancy Hepatocellular carcinoma (HCC), pancreatic cancer Development of thrombus is a poor prognostic factor in HCC Hypercoagulable states Factor V Leiden, Prothrombin gene mutation, Protein C deficiency,, Protein S deficiency, Antithrombin III deficiency Myeloproliferative disease Infection Rare cause of PVT Intra-abdominal abdominal infection such as diverticulitis and appendicitis can cause a pylephlebitis of portal vein In the pediatric population, omphalitis (infection of umbilical stump) can spread to portal vein Post surgical Post splenectomy Post transplant, secondary to surgical manipulation of portal system stem Often multifactorial Etiology unknown in up to 1/3 of cases
7 Portal vein thrombosis is a radiologic diagnosis. Let s s take a look at the various options for imaging.
8 PVT: Menu of Radiologic Tests Test Indications & Findings Advantages Disadvantages Ultrasound Echogenic thrombus No No blood flow on Doppler Non Non invasive Readily Readily available Operator dependent Acute Acute thrombi could be hypoechoic or anechoic Difficult Difficult to assess splenic vein and other branches due to background liver echogenicity Contrast CT Non-enhancing filling defect within lumen Rim Rim enhancement Variations with phase Readily Readily available Non Non operator dependent Contraindicated in patients with contrast allergy, renal insufficiency MRI Can Can see increased signal intensity on T2 Non Non invasive No No contrast ExpenseExpense Claustrophobia Ascites Ascites may cause artifact Angiography Often Often pre-operative or during TIPS Filling Filling defect Gold Gold standard Shows Shows extent, location and severity of thrombus InvasiveInvasive Contrast Contrast MRA / CTA Filling Filling defect Good Good visualization of collaterals InvasiveInvasive Contrast Contrast
9 Anatomy Review Portal venogram showing main, left and right portal veins BIDMC PACS
10 Ms. S: Patent Left Portal Vein and Left Portal Vein thrombosis on CT Abdominal CT 1 month prior to admission Abdominal CT on admission * * * * C+ Abdominal CT, axial image, portal venous phase. BIDMC PACS BIDMC PACS Patent left portal vein Left portal vein occlusion * ascites
11 Portal Vein Thrombus: CT Findings Non enhancing filling defect within lumen Rim enhancement Flow through dilated vasa vasorum Increased flow around periphery of clot Can see phase dependent changes Enhancement during arterial phase as hepatic artery compensates for decreased blood flow from portal system Decreased attenuation during portal venous phase Occasionally can see calcifications in chronic thrombus Can see arterial phase enhancement if malignant thrombus
12 Ultrasound of Portal System Can detect presence, direction and characteristics of portal venous blood flow hepatopetal = flow toward liver Normal direction of portal venous flow hepatofugal = flow away from liver Normal portal venous flow is continuous hepatopetal with minimal respiratory variation Hepatofugal flow in the portal system develops when pressure in portal system is greater than pressure in collateral vessels Thrombus in portal vein would show absence of flow and an echogenic thrombus
13 Ms. S: Patent Portal Vein on US Transverse color doppler ultrasound of main portal vein Flow depicts patent main portal vein Transverse color doppler ultrasound of left portal vein Flow depicts patent left portal vein Possible small echogenic thrombus in left portal vein
14 Ms. S: Clinical Course Ulcerative Colitis Treated with an infusion of Remicade, a TNF- inhibitor Received 2 units packed red blood cells Primary biliary cirrhosis Developed hepatic encephalopathy Treated with lactulose and rifaximin Therapeutic paracentesis Tested positive for HIT antibodies Lower extremity ultrasound showed no DVTs Acute PVT Review of outside hospital CT showed left portal vein thrombus Doppler ultrasound revealed patent left portal vein, though non-occlusive occlusive thrombus could not be ruled out Anticoagulation contraindicated given GI bleeding Scheduled for follow up CT in 2 weeks Represented within 2 weeks for acute decompensation of end stage liver disease
15 Ms. S underwent ultrasound and CT scans which showed progression of her portal vein thrombus.
16 Ms. S: Portal Vein Thrombus on Ultrasound BIDMC PACS Previous Ultrasound Color doppler ultrasound, transverse view of liver No flow in main portal vein Echogenic thrombus BIDMC PACS Next Step?
17 Ms. S: Main Portal Vein Thrombus on CT * * Non enhancing filling defect in main PV Multiple collateral vessels ascites * * Contrast enhanced abdominal CT, axial images, portal venous phase BIDMC PACS
18 Ms. S: Left and Right Portal Vein Thrombi on CT Contrast enhanced abdominal CT, axial images, portal venous phase Left portal vein occlusion Right portal vein occlusion BIDMC PACS
19 Ms. S: Superior Mesenteric Vein Thrombus on CT Filling defect in superior mesenteric vein (SMV) Contrast enhanced abdominal CT, axial images, portal venous phase BIDMC PACS
20 Ms. S: Main Portal Vein and SMV Thrombus on CT Thrombus in main portal vein * Thrombus in SMV * * Ascites Multiple collateral vessels Contrast enhanced abdominal CT, portal venous phase, maximum intensity projection, coronal reconstruction BIDMC PACS
21 Ms. S: Interim Clinical Course Acute liver failure MELD 28, up from 13 during last admission Total bilirubin 16.4, up from 2.6 during last admission She developed a leukocytosis which was concerning for possible spontaneous bacterial peritonitis Hypotensive and tachycardic Placement of central line She became hypoxic to 88% on RA Chest x-ray x to evaluate hypoxia
22 BIDMC PACS Ms. S: Pneumothorax and Pleural Effusion on Chest X-RAYX * * * Chest tube Portable anterior-posterior chest x-rayx Right pleural effusion Left pneumothorax Collapsed left lung Central line possible cause of pneumothorax Chest tube with re-expanded left lung
23 Ms. S: Clinical Progression Significant clinical decompensation,, most likely due to occlusive portal vein thrombus Anticoagulation contraindicated given GI bleed The transplant team was consulted She was not a candidate for transplant because of her ulcerative colitis and possible sepsis She developed disseminated intravascular coagulation and methicillin-resistent staph aureus bacteremia She was ultimately made comfort measures only and passed away soon after
24 Ms. S s S s case demonstrated an acute, bland thrombus in the setting of cirrhosis. Let s s move on to see features of portal vein thrombus caused by a tumor in two companion patients
25 Companion Patient #1: Portal Vein Tumor Thrombus on CT 71 year old male with a history of hepatitis B who presents with two days of epigastric pain, frequent bowel movements and fecal incontinence Large hypoattenuating mass in right lobe of liver extending into portal vein C+ CT scan, axial images, portal venous phase BIDMC PACS
26 Tumor Thrombus: Radiologic Features Companion patient #1 BIDMC PACS Often see dilation of portal vein Diameter > 23mm * Intrathrombus neovascularity Arterial enhancement on CT Pulsatile flow on doppler US Thread and streak sign multiple enhancing intraluminal smaller vessels that can be seen at arterial phase imaging Contiguity to tumor Often with direct invasion *Tublin et al., Benign and malignant portal vein thrombosis.
27 Companion Patient #1: Inferior Vena Cava and Right Atrial Thrombi on CT BIDMC PACS IVC tumor thrombus BIDMC PACS Right atrial tumor thrombus
28 Companion Patient #2: PVT and Cavernous Transformation on CT 52 year old male with a three year history of renal cell carcinoma with liver metastases and known left portal vein thrombus BIDMC PACS BIDMC PACS Contrast enhanced abdominal CT, portal venous phase, maximum intensity projection, coronal reconstruction Left portal vein thrombus Multiple hypoattenuating lesions consistent with metastatic disease Multiple serpiginous periportal collateral vessels = CAVERNOUS TRANSFORMATION
29 Cavernous Transformation Formation of multiple venous collaterals when portal system is obstructed Necessary to drain tributaries of portal vein and maintain adequate ate hepatic perfusion Can be porto-porto (bypassing obstruction) or porto-systemic Good imaging of collaterals is important for surgical planning Imaging techniques CT, US, MRI, CTA, MRA Appearance: spongelike, serpiginous, corkscrew, netlike
30 Collateral Circulation Reversal of flow into low pressure collateral veins due to portal hypertension Major porto-systemic collaterals Left gastric vein, short gastric veins, esophageal veins Anastomose with azygous system Esophageal varices Para-umbilical and abdominal wall veins Caput medusa Splenorenal shunts Rectal varices Bleeding from varices causes significant morbidity
31 Companion Patient #3: Porto-Porto Collaterals on CT and MRA Lee et al: Portal vein thrombosis: CT features Cavernous transformation on contrast enhanced CT scan, portal venous phase Wang et. al Cavernous transformation of the portal vein: 3D dynamic contrast enhanced MR angiography Cavernous transformation on MRI angiography
32 Companion Patient #4: Cirrhosis on CT scan 57 year old male with a history of alcoholic cirrhosis, portal hypertension, gastroesophageal varices and chronic portal vein thrombosis Presented for possible transjugalar intrahepatic porto-systemic shunt (TIPS) procedure to alleviate portal hypertension Shrunken, cirrhotic liver BIDMC PACS
33 The patient had a percutaneous venogram to visualize the portal system during his TIPS attempt
34 Companion Patient #4: Portal Vein Thrombus on Percutaneous Venogram Blocked main portal vein Large splenic collateral to left and right portal veins effectively replacing main portal vein BIDMC PACS
35 Treatment Modalities for PVT Treatment dependent on nature of clot Acute, recent or chronic Treat for varices with sclerotherapy or banding Direct thrombolysis with tpa or streptokinase in acute clot Long-term anticoagulation At least three months, longer if underlying hypercoagulable state Mechanical thrombectomy TIPS Controversial Contraindicated if complete occlusion or significant cavernous transformationt Can reduce risk of variceal bleeding Often in conjunction with mechanical thrombectomy or direct thrombolysis Indications: failed sclerotherapy, ascites,, pre-operative Risk of embolism
36 Summary Portal vein thrombus is rare in the general population but not rare in the cirrhotic population Often asymptomatic Consider workup in a patient with variceal bleed, new ascites or sudden decompensation in a patient with cirrhosis Ultrasound and CT are first line for diagnosis
37 Acknowledgments Brian Midkiff, MD Martin Smith, MD Salamao Faintuch, MD Erica Gupta, MD Sadhna Nandwana, MD Gillian Lieberman, MD Maria Levantakis
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