Serum ammonia as a non-invasive marker for early prediction of esophageal varices.

Abstract

There is a growing need for identification of non-endoscopic, non-invasive methods that can accurately predict esophageal varices (EV). Previous studies found an inconclusive correlation between blood ammonia level and the presence and size of EV. We aimed at assessing the value of serum ammonia as a non-invasive method for early prediction of EV. The study included 204 patients with HCV-related cirrhosis. The selected patients were categorized into two groups: patients with EV and those without, also patients with no or small EV and with large EV group. All patients underwent a complete biochemical workup, ultrasound and upper GI endoscopy. Child-Pugh class, Model of End-Stage Liver Disease (MELD) score and platelet count/splenic diameter ratio, and serum ammonia level. There was a statistical difference between the two groups of patients regarding the following parameters: serum ammonia, international normalized ratio, portal vein diameter, spleen diameter, Child-Pugh class, MELD score, platelet count/splenic diameter ratio, aspartate aminotransferase-to-platelet ratio index, alanine aminotransferase-to-aspartate aminotransferase ratio, Forns index, FIB-4 and King's score. Serum ammonia could predict the presence of EV using a cutoff value of 82 (µmol/L) with a sensitivity of 92.3%, specificity 92%. In addition, a cutoff of 95.5 (µmol/L) could predict large EV with a sensitivity of 92.7% and a specificity of 92.3%. Serum Ammonia in cirrhosis with large EV was 143 ± 39 µmol/L and in cirrhosis with small/without EV was 80.7 ± 9.7 µmol/L (P < 0.0001). Platelet/spleen ratio was 555.9 ± 187.3 in cirrhosis with EV and 694.4 ± 74.2 in cirrhosis without EV (P < 0.0001). Platelet/spleen ratio was 407.7 ± 107.1 in cirrhosis with large EV and 690.4 ± 103.7 in cirrhosis with small/without EV (P < 0.0001). Serum ammonia can accurately predict the presence and the size of EV in patients with liver cirrhosis with high sensitivity and specificity.