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

INTRODUCTION: 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. AIM: We aimed at assessing the value of serum ammonia as a non-invasive method for early prediction of EV. PATIENT AND METHODS: 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. RESULTS: 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 (micromol/L) with a sensitivity of 92.3%, specificity 92%. In addition, a cutoff of 95.5 (micromol/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 micromol/L and in cirrhosis with small/without EV was 80.7 +/- 9.7 micromol/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). CONCLUSION: Serum ammonia can accurately predict the presence and the size of EV in patients with liver cirrhosis with high sensitivity and specificity.