Observation of thoracic duct morphology in portal hypertension by endoscopic ultrasound

Background: Thoracic duct dilation has been demonstrated in portal hyperten sion and hepatic cirrhosis by lymphangiography and laparotomy and at autops y. it is thought to be secondary to increased hepatic lymph flow and has be en described in the absence of ascites or esophageal varices. The aim of th e present study was to observe thoracic duct morphology by endoscopic ultra sound in various subsets of patients with portal hypertension and hepatic c irrhosis and also to validate existing radiologic/surgical data. Methods: The thoracic duct of 33 patients with cirrhosis and portal hyperte nsion was studied by endoscopic ultrasound. Patients were divided into four groups: 1, patients with ascites and esophageal varices; 2, esophageal var ices without ascites; 3, without esophageal varices or ascites; 4, extrahep atic portal hypertension due to pancreatic malignancy. The thoracic duct di ameter was also measured in 14 control subjects (group 5). Results: When the thoracic duct diameter for the five groups was compared w ith analysis of variance, significance was p < 0.0001; by pairwise comparis on, group 1 differed from the other four groups (p < 0.05). Thoracic duct d ilation (5.61 mm) was seen in group 1 patients, whereas no dilation was pre sent in groups 2 through 4. Additionally, thoracic duct diameter in 33 port al hypertensive and/or cirrhotic patients was significantly different from that in the 14 control subjects (p = 0.003). Conclusion: The thoracic duct can be reliably identified by EUS in patients with hepatic cirrhosis and portal hypertension. Dilation of the duct is se en only in patients with hepatic cirrhosis, ascites, and esophageal varices . No thoracic duct dilation is present in extrahepatic portal hypertension. Contrary to existing radiologic/surgical data, thoracic duct dilation is n ot seen in all patients with hepatic cirrhosis and portal hypertension sign ifying advanced disease. A dilated thoracic duct by endoscopic ultrasound s hould be considered yet another sign of portal hypertension.