Published online Apr 28, 2015. doi: 10.3748/wjg.v21.i16.4946
Peer-review started: October 18, 2014
First decision: December 2, 2014
Revised: December 31, 2014
Accepted: February 12, 2015
Article in press: February 13, 2015
Published online: April 28, 2015
AIM: To identify criteria for predicting successful drainage of unresectable malignant hilar biliary strictures (UMHBS) because no ideal strategy currently exists.
METHODS: We examined 78 patients with UMHBS who underwent biliary drainage. Drainage was considered effective when the serum bilirubin level decreased by ≥ 50% from the value before stent placement within 2 wk after drainage, without additional intervention. Complications that occurred within 7 d after stent placement were considered as early complications. Before drainage, the liver volume of each section (lateral and medial sections of the left liver and anterior and posterior sections of the right liver) was measured using computed tomography (CT) volumetry. Drained liver volume was calculated based on the volume of each liver section and the type of bile duct stricture (according to the Bismuth classification). Tumor volume, which was calculated by using CT volumetry, was excluded from the volume of each section. Receiver operating characteristic (ROC) analysis was performed to identify the optimal cutoff values for drained liver volume. In addition, factors associated with the effectiveness of drainage and early complications were evaluated.
RESULTS: Multivariate analysis showed that drained liver volume [odds ratio (OR) = 2.92, 95%CI: 1.648-5.197; P < 0.001] and impaired liver function (with decompensated liver cirrhosis) (OR = 0.06, 95%CI: 0.009-0.426; P = 0.005) were independent factors contributing to the effectiveness of drainage. ROC analysis for effective drainage showed cutoff values of 33% of liver volume for patients with preserved liver function (with normal liver or compensated liver cirrhosis) and 50% for patients with impaired liver function (with decompensated liver cirrhosis). The sensitivity and specificity of these cutoff values were 82% and 80% for preserved liver function, and 100% and 67% for impaired liver function, respectively. Among patients who met these criteria, the rate of effective drainage among those with preserved liver function and impaired liver function was 90% and 80%, respectively. The rates of effective drainage in both groups were significantly higher than in those who did not fulfill these criteria (P < 0.001 and P = 0.02, respectively). Drainage-associated cholangitis occurred in 9 patients (12%). A smaller drained liver volume was associated with drainage-associated cholangitis (P < 0.01).
CONCLUSION: Liver volume drainage ≥ 33% in patients with preserved liver function and ≥ 50% in patients with impaired liver function correlates with effective biliary drainage in UMHBS.
Core tip: An ideal biliary drainage strategy for unresectable malignant hilar biliary strictures (UMHBS) has not been defined. The aim of our study was to identify useful criteria for predicting successful drainage of UMHBS. In the present study, multivariate analysis revealed that liver function and drained liver volume calculated by computed tomography volumetry (CTV) are independent factors of drainage effectiveness for UMHBS. Receiver operating characteristic analysis showed cutoff values of 33% of liver volume for patients with preserved liver function and 50% for patients with impaired liver function. Before attempting biliary drainage procedures, establishing an appropriate drainage strategy using CTV is important.