Suprapapillary Metal Stent vs. Routine Transpapillary Drainage in Malignant Hilar Biliary Obstruction (SMART-B Trial)

Malignant hilar biliary obstruction is a condition in which the bile ducts near the liver become blocked due to cancer. This blockage can lead to jaundice (yellowing of the skin and eyes), itching, infection, and impaired liver function. To relieve the obstruction, doctors commonly perform procedures to drain bile and restore its flow. There are different techniques available for biliary drainage. One common method is percutaneous transpapillary internal-external drainage, in which a catheter is placed through the liver and across the natural opening of the bile duct into the intestine. Another approach is percutaneous suprapapillary drainage using a self-expanding metal stent, which allows bile to drain without crossing into the intestine and may reduce the risk of contamination and infection. Currently, there is no clear consensus on which of these two techniques is safer or more effective for patients with malignant proximal biliary obstruction. Some studies suggest that avoiding manipulation of the intestinal opening of the bile duct may reduce complications such as infection, but high-quality comparative evidence is lacking. The purpose of this study is to compare percutaneous suprapapillary drainage with a self-expanding metal stent versus routine percutaneous transpapillary internal-external drainage in patients with malignant proximal biliary obstruction. The study aims to compare the rate of drainage-related complications between the two techniques, as well as to evaluate treatment success, stent patency, and the need for reintervention. In addition, in patients with potentially resectable disease undergoing preoperative biliary drainage, the study will assess and compare surgical outcomes between the two approaches. The results of this study may help determine the safest and most effective drainage strategy for these patients and improve future clinical decision-making.

Inclusion Criteria: 1. Age \>18 years. 2. Malignant proximal biliary obstruction on imaging (magnetic resonance cholangiopancreatography or contrast-enhanced abdominal computed tomography) with histopathological confirmation or high clinical and radiological suspicion. 3. Total bilirubin \> 3 mg/dL. 4. Patients not candidates for potentially curative surgical resection due to locally advanced disease, metastatic disease, or inadequate clinical condition. 5. Patients with potentially resectable neoplasms, defined as the possibility of achieving complete resection (R0), who meet at least one of the following criteria: 5.1 Estimated future liver remnant \10 mg/dL for more than 14 days. 5.3 Malnutrition, defined as ≥10% unintentional weight loss or albumin \38°C) and leukocytosis (white blood cell count \>10,000/mm³). 4. Uncorrectable coagulopathy. 5. Iodinated contrast allergy not amenable to desensitization.