Portal vein thrombosis – etiology, clinical features, complications.

Abstract

SUMMARY: Portal vein thrombosis as a condition is more frequently discovered in recent years, due to the routine use of imaging procedures, especially Duplex and color Doppler ultrasound, in everyday clinical practice. Portal vein thrombosis either acute or chronic, is usually presented with non-specific clinical features. Etiology can be different, systemic and local factors are involved, among them prothrombotic disorders, cancer and cirrhosis, are the most frequent. Our study included 16 patients (pts), admitted to our hospital between 2010 and 2012, with varying clinical symptoms, starting from abdominal pain, up to abundant variceal bleeding. Duplex and color Doppler ultrasound examination revealed portal vein thrombosis in all of the them, the diagnosis was confirmed by the means of contrast enhanced Computed Tomography, Magnetic Resonance Imaging or during surgery. In patients presented with variceal bleeding, endoscopic measures for bleeding management were undertaken immediately, whereas patients presented with non-bleeding episodes required anticoagulant treatment (i.v. Heparin, s.c. Clexane, maintened by oral Syntrom). The treatment outcome was different in different patients, mostly depending on etiology and clinical features, furthermore the final assessment of the treatment was difficult to achieve, due to the retrospective nature of the study and the limited period of time. INTRODUCTION: When we speak about portal vein thrombosis, we mean exactly: thrombosis of the main portal vein and it’s tributaries, superior and inferior mesenteric vein and splenic vein. Thrombosis occurs in different segments of the main portal vein, just in extrahepatic part, or in whole portal trunk and it’s intrahepatic branches. Occlusion by the clot may be complete, or occurring in a part of the vessel, with a present blood flow around the clot. Thrombosis of the splenic vein can be isolated from the rest of the portal venous system, whereas occlusion of the superior and inferior mesenteric vein, usually occurs together with main portal vein thrombosis. The diagnosis of portal vein thrombosis may be established in the “acute phase”, or in advanced “chronic phase” with already developed complications as a result of portal hypertension. The diagnosis of portal vein thrombosis is much more frequently established recently, due to the routine use of Doppler ultrasonography during abdominal examinations. It has been shown that overall risk of getting portal vein thrombosis in general population during lifetime is 1% , whereas in cirrhotic patients is much more higher, from 10% to 20%. Etiology of portal vein thrombosis can be different, and systemic and local risk factors are involved. The most frequent are prothrombotic disorders, established cirrhosis, cancer, abdominal infection/inflammation and intra-abdominal surgery. Risk factors remain unknown in only small percent of cases. The cause of portal vein thrombosis in cirrhotic patients differs from non-cirrhotics, it is mainly because the reduced and extremely slow blood flow, which sometimes becomes retrograde in patients with portal hypertension. These two conditions can lead to blood clot formation in portal vein, despite the decreased production of prothrombin complex factors in the diseased liver. Depending on etiology, and weather portal vein thrombosis is in acute or chronic phase, clinical presentation will vary. Patients refer to the hospital with abdominal pain, nausea and vomiting due to the bowel ischemia from congestion, or with variceal bleeding as a result of portal hypertension and developed collateral circulation. Patients with portal vein thrombosis without cirrhosis will develop varices but no ascites, because the liver is not involved. When ascites is present it implies presence of underlying liver disease. Bleeding can be presented either as upper (haemathemesis and/or melaena) or lower gastrointestinal bleeding (enteral/rectal). Treatment strategies of portal vein thrombosis are still not completely defined, mainly because of the different etiologies, and absence of sufficient prospective studies. When thrombotic disorder is the main risk factor, anticoagulation treatment should be introduced immediately. We may use this treatment even in cirrhotic patients , with no recent evidence of variceal bleeding, in order to resolve the clot and achieve revascularization, which is important for decreasing portal hypertension and avoiding potential bowel ischaemia and infarction. Anticoagulation therapy is not an issue if patient is referring with variceal bleeding and portal vein thrombosis. THE AIM OF THE STUDY which is retrospective is on establishing etiology, diagnosis, complications and treatment of 16 patients admitted to the hospital with portal vein thrombosis, detected by duplex/color Doppler ultrasound. MATERIAL AND METHODS Study includes 16 patients, 9 male and 7 female (age range 41 to 74) referred to the hospital between 2010 to 2012y. Patients were admitted to the hospital with variety of clinical presentations: from abdominal pain followed by nausea, vomiting and fever; through weight loss, malaise and yellowing of the skin; or with different forms of acute gastrointestinal bleeding. On admission all patients underwent routine blood testing, coagulation screen, liver and renal functional biochemistry. Portal vein thrombosis was diagnosed by duplex/color Doppler ultrasound, and was confirmed in three patients by contrast enhanced Computed Tomography, in two patients by Magnetic Resonance Imaging, and in one patient during surgery procedure. There was no need of second imaging procedure in rest of the cases. In determining the etiology of thrombosis, fine needle aspiration biopsy under ultrasound control, as well as endoscopic biopsy were used. Endoscopic procedures were used for detecting and treating complications such as gastric and esophageal varices. RESULTS Duplex and color Doppler ultrasound revealed isolated thrombosis of splenic vein in 2 (12,5%) pts; thrombosis of the main portal trunk without involvement of intrahepatic branches in 6 (37,5%) pts; thrombosis of the whole portal vein (extra and intrahepatic) in 3 (18,7%) pts; thrombosis of the whole portal system (portal, superior mesenteric and splenic vein) in 3 (18,7%) pts and cavernous transformation of the portal vein in 2 (12,5%) pts. Regarding etiology, malignancy was discovered in 4 (25%) cases ( hepatocellular carcinoma in 2 pts, gastric carcinoma in one, and retroperitoneal malignancy in one); 5 (31%) of the cases had proven liver cirrhosis; in 2 (12,5%) cases thrombosis was a sequel of previous abdominal inflammation (acute pancreatitis) and in 1(6,25%) case sequel of previous abdominal surgery; 3 (18,7%) pts had prothrombotic disorder and in one case the cause of thrombosis remained unknown (duodenal malignancy suspected, but without histological evidence). Main complications of portal vein thrombosis, sequel of developed portal hypertension, in a form of esophageal and gastric varices were detected just in 8 (50%) pts. Esophageal varices were detected in 6 (37,5%) pts; gastric (subcardial ) varices in 5 (31%) pts and in 1 (6,25%) pt varices were detected in the antral region of the stomach. Same number of patients 8 (50%) ,were admitted to the hospital with bleeding as a leading symptom, but not all of them had variceal bleeding. One case (6,25%) suffered from intestinal bleeding (difficult general condition did not allowed any further investigations); one patient (6,25%) had bleeding gastric carcinoma; onether one (6,25%) had bleeding duodenal tumor (not confirmed as malignancy); bleeding from gastric ulcer (in presence of gastric varices) was confirmed in one case(6,25%); 3 pts (18,7%) had bleeding from esophageal varices and one patient (6,25%) had gastric-variceal bleeding. Bleeding from esophageal varices was urgently managed with band-ligation in 2 cases, and with endoscopic sclerotherapy in 1 case; patient with ulcer bleeding was treated by adrenalin infiltration; while bleeding from gastric varices was temporarily stopped by applying histoacryl glue, unfortunately emergency surgery was needed due to heavy bleeding reccurence. Patients presented with bleeding due to malignancy of stomach and duodenum, and a patient with intestinal bleeding were medically treated, with PPI , transfusions of fresh frozen plasma and red-blood cells. Patients presented without bleeding : 3 pts with prothrombotic disorder and acute portal thrombosis; 1 pt with thrombosis of whole portal system as a sequel of previous abdominal surgery; 2 pts with cirrhosis, portal thrombosis and non-bleeding varices, and one patient with liver carcinoma on underlying cirrhosis without bleeding but with symptoms of bowel ischaemia, underwent anticoagulation treatment. Anticoagulation treatment was started by i.v. Heparin for 3 days, followed by 7 days s.c. Clexane (2x40mg) and finally maintained on oral anticoagulant therapy (Syntrom). Patients with cirrhosis and chronic portal vein thrombosis, as well as the patients with cavernous transformation of portal vein , without signs of active bleeding, were medically treated with PPI, β-blockers, transfusions of fresh frozen plasma and red-blood cells. DISCUSSION Portal vein thrombosis in clinical practice is usually presented as a sequel of decreased hepatopatal blood flow in cirrhotic patients (10-20%), or as a complication of abdominal malignancy (hepatocellular, pancreatic, gastric carcinoma), although in a few cases prothrombotic tendency and abdominal inflammation (acute pancreatitis, diverticulitis) may be the underlying causes. Recent years, portal vein thrombosis is more frequently detected in clinical practice, due to the routine use of duplex/color Doppler ultrasound, a non-invasive, safe, easily reproducible, and cost-effective method, comparing with other imaging procedures. In case of non-conclusive finding, diagnosis confirmation can be made with contrast-enhanced CT or MRI. Most frequent, and at the same time, life-threatening presentation of portal vein thrombosis is esophageal and/or gastric varices bleeding. This presentation is a medical emergency , and requires immediate haemostatic procedures , usually endoscopic ligation/sclerotherapy, but sometimes there is also need of urgent surgical treatment. The treatment of portal vein thrombosis depends on etiology and whether it is discovered in acute, or in chronic phase. Patients who suffer from thrombosis due to a prothrombotic disorder should be immediately anticoagulated. When thrombosis is discovered in cirrhotic patients with decreased blood flow, anticoagulation treatment may be used in hope of recanalization of portal vein, in order to postpone portal hypertension, only in patients with non-bleeding varices. In case of variceal bleeding, anticoagulant treatment is not advisible. In such cases literature review is recommending clot removal during TIPS or surgical procedure. However, such a risk should be undertaken only after managing the variceal bleeding endoscopically.