Biliary drainage strategy of unresectable malignant hilar strictures by computed tomography volumetry

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 livercirrhosis)and 50%for patients with impaired liver function(with decompensated liver cirrhosis).The sensitivity and specificity of these cutoff values were82%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.