Correlation between liver volume drainage and clinical success after endoscopic biliary drainage of hilar malignant obstruction

• The main cause of hilar obstruction was cholangiocarcinoma (32.9 %) followed by lymph node metastasis (23.2 %). • Technical success was achieved in 91.5 %, clinical success in 60 %. • A significant correlation between clinical success rate was found when at least 50 % of viable parenchyma was drained (p = 0.016; OR = 4.15, 95 % CI 1.4–12.5). • Considering liver sectors, higher clinical success rates were found when at least 2 sectors were drained (p < 0.001; OR = 8.50, 95 % CI 2.7–26.7). • Correlation between unilateral versus bilateral drainage and clinical success was not statistically significant. Malignant hilar obstruction usually presents in advanced-stage disease with a poor prognosis. Effective biliary drainage is essential for the beginning of palliative chemotherapy. There is a debate on the amount of liver parenchyma that should be drained to achieve clinical success. This study aimed to correlate the volume of liver drained with clinical success rate. The authors conducted a retrospective study including patients with malignant hilar biliary obstruction who underwent retrograde endoscopic cholangiography for biliary drainage from January 2014 to December 2018. The main outcome was a correlation of clinical success rate with hepatic volume drained. Secondary outcomes were correlation of clinical success rate with the quantity of liver sectors drained and unilateral versus bilateral drainage. 82 patients met inclusion criteria (58.5 % female), with a mean age of 60±13 years. The main cause of hilar obstruction was cholangiocarcinoma (32.9 %) followed by lymph node metastasis (23.2 %). Technical success was achieved in 75 patients (91.5 %), and clinical success in 45 patients (60 %). The authors found a significant correlation between clinical success rate when at least 50 % of viable parenchyma was drained (p = 0.016; OR = 4.15, 95 % CI 1.4–12.5). Considering liver sectors, higher clinical success rates were found when at least 2 sectors were drained (p < 0.001; OR = 8.50, 95 % CI 2.7–26.7). The correlation between unilateral versus bilateral drainage and clinical success was not statistically significant. Drainage of at least 50 % of volume hepatic parenchyma was associated with better outcomes as well as drainage of at least 2 hepatic sectors, regardless of if unilateral or bilateral.