The incidence of portal hypertension in children with choledochal cyst and the correlation of nitric oxide levels in the peripheral blood with portal pressure and liver histology

BACKGROUND AND AIMS: Symptomatic portal hypertension (PHT) as a complication of the choledochal cyst (CDC) is well-known, but the actual incidence of PHT in CDC has not been studied. This study was undertaken to evaluate the incidence of PHT in patients of CDC and correlate portal pressure (PP) with liver histology and blood nitric oxide (NO) levels. MATERIALS AND METHODS: In this cross-sectional study, PP was measured after surgical access but before any mobilization of the cyst by directly cannulating a tributary of portal vein (preoperative PP) and at completion of surgery before closure (postoperative PP). Blood sample for NO and liver function tests (LFTs) was taken before surgery and during subsequent follow-up at 1-month, 3 months, and 6 months. Liver histology was assessed under parenchymal, bile duct, and portal parameters. RESULTS: Measurement of PP and blood levels of NO was done in 20 patients. Mean preoperative PP was 16.45 ± 7.85 mmHg, and the median pressure was 14 mmHg (range 9-43). Mean of the postoperative PP was 14 ± 6.87 mmHg, and median pressure was 11.5 mmHg (range 7-37). The mean level of NO in the preoperative period was 11.85 ± 4.33 μmol/l, and median was 11.605 (range 5.24-22.77) μmol/l. NO levels at the first follow-up (1-month postoperative) were 5.96 ± 4.56 μmol/l and median value of 4.9 (range 1.74-23.56) μmol/l. Likewise, the mean and median values of NO at 3 months were 5.59 ± 7.15 μmol/l and median value of 3.71 (range 1.49-34.74) μmol/l. The mean and median levels of NO at 6 months postoperative were 5.08 ± 2.22 μmol/l and median of 4.59 (range 2.32-12.46) μmol/l. The fall in PP immediately after surgery was consistent and statistically significant (P = 0.001). There was statistically significant fall in the NO levels in the postoperative period as compared to the preoperative levels (P = 0.002). Bile duct proliferation was significantly correlated with PP (P = 0.05). Blood levels of NO closely followed the PP in the preoperative period and fell to baseline in subsequent follow-up. There was no statistically significant correlation between age at presentation, LFT and postoperative complications with either PP or NO levels. CONCLUSIONS: In this study, all patients with CDC had some degree of PHT. Measurement of PP and liver histology should be part of standard management protocol to take timely preventive measures so as to avoid life-threatening manifestations of PHT.