Factors influencing blood bilirubin decline duration in distal malignant biliary obstructions with biliary drainage

Distal malignant biliary obstructions (DMBO) are one of the causes of extrahepatic jaundice. For these patients, percutaneous biliary cholangiography (PTC) and endoscopic retrograde cholangiopancreatography (ERCP) procedures are performed for preoperative or palliative biliary drainage. The aim of this study is to investigate the factors affecting the duration of bilirubin decrease after interventional procedures in patients with DMBO. The study included total of 34 patients with DMBO who presented with jaundice to the Gastroenterology and Non-Vascular İnterventional Radiology Departments of Hacettepe University between July 2022 and June 2023. During ERCP metal/plastic stents and during PTC 8/10 F catheters were placed for drainage. Before the procedures, patients' laboratory test results (platelet count, INR, liver function tests, total and direct bilirubin levels) and imaging were recorded. Total and direct bilirubin values were recorded on 1st post-procedure day, 1st week, 2nd week, 3rd week and 4th weeks. The rates of decrease of total and direct bilirubin levels during follow-up were calculated, and complications occurring after the procedures were recorded. The rate of bilirubin decrease was compared with the examined parameters, with p<0.05 considered statistically significant. In our study, a significant decrease was observed in total and direct bilirubin values on the 1st day after the procedure in patients who underwent PTC compared to ERCP (before PTC procedure, the total/direct levels were 10.54/6.25 mg/dL, after the procedure 7.15/3.89, p=0.04, p=0.03 respectively). It was observed that the group with cholangitis had a longer duration of bilirubin decrease (p<0.05). Correlation analysis revealed a significant negative correlation between pre-procedure ALT and post-procedure total bilirubin (1st day-1st week r:-0.26, p=0.03, 2nd-4th week r:-0.24, p=0.04), AST and total bilirubin (1st day - 1st week r:-0.31, p=0.01, 2nd-4th week r:-0.26, p=0.03) decrease rates. As a result, we identified a negative correlation between liver function tests and the duration of bilirubin decrease in the blood. Furthermore, we found that in patients underwent PTC, bilirubin levels decreased faster on the 1st day after the procedure, and cholangitis reduced the rate of bilirubin decrease.