Value of portal venous system radiological indices in predicting esophageal varices

INTRODUCTION Portal hypertension results from increased resistance to portal blood flow and has the potential complications of variceal bleeding and ascites. The splenoportal veins increase in caliber with worsening portal hypertension, and partially decompress by opening a shunt with systemic circulation, ie, a varix. In the event of portosystemic shunting, there is a differential decompression across the portal vein and splenic vein (portal vein > splenic vein), with a resultant decrease in the ratio of portal vein diameter to that of splenic vein. Portal vein to splenic vein diameter ratio and gradient could be valuable tools in predicting the presence of portosystemic shunting. METHODS We retrospectively reviewed patients with cirrhosis who underwent esophagogastroduodenoscopy (EGD) for variceal screening and had a computerized tomogram (CT) of the abdomen within 6 months of the index endoscopic study, between January 2009 and December 2013. Patients on nonselective beta blockers, patients with presinusoidal portal hypertension (portal vein thrombosis or extrinsic compression), and patients who had undergone portosystemic shunting procedures (transjugular intrahepatic portosystemic shunt [TIPS]) or balloon-occluded retrograde transvenous obliteration (BRTO) were excluded from the study. Splenic and portal vein diameters were measured (in mm) just proximal and distal to the splenomesenteric venous confluence, respectively. RESULTS A total of 164 patients were included in the study; of these, 60% (n=98) were male and 40% (n=66) were female. The mean age of the study population was 58.7 years. A total of 126 patients (77%) had varices, while 38 patients (33%) did not. The mean Model for End-Stage Liver Disease (MELD) score was 5.9 for those who had varices as compared with 7.03 for those who did not. The mean of ratios of portal vein to splenic vein diameters in patients with varices was 1.27 (±0.2), while it was 1.5 (±0.23) in those without varices. This difference was statistically significant (P<0.001). The mean of the gradients between the portal vein and splenic vein diameters was 2.7 (±2) mm for patients with varices as compared with 5 (±1.8) mm in those without varices. This difference was also statistically different (P<0.001). These correlations were statistically significant even after controlling for age, sex, and MELD. These radiological indices also had statistically significant correlations with the presence of gastric varices (P=0.018 for the ratio and P=0.01 for the gradient). A discriminant function analysis was performed that generated the equation: D = 2.68 (ratio of portal vein to splenic vein diameters) + 0.187 (gradient of portal vein to splenic vein diameters, in mm) - 4.152. This equation had a very high sensitivity, of 95%, but low specificity, of 26.3%, in predicting the presence of esophageal varices. CONCLUSION Both venous diameter ratio (portal vein size/splenic vein size) and venous diameter gradient in mm (portal vein size - splenic vein size) calculated from CTs of the abdomen were good predictors of presence of esophageal varices. These parameters might be useful in stratifying patients at risk of developing esophageal varices who are poor candidates for endoscopic evaluation.