Numerical simulation of biliary stent clogging

A.G. Kuchumov, M. Kamaltdinov, A. Selyaninov, V. Samartsev

Abstract: Biliary stenting to restore bile flow has been using for 40 years. However, the long-term effects of such procedure are not satisfactory due to jaundice occurrence caused by plastic stent clogging. Bacteria, biofilms formation, and biliary sludge lead to the biliary plastic stent occlusion. The main components of biliary sludge are cholesterol, calcium bilirubinate, calcium palmitate. An average period of plastic stent clogging is 3–6 months. Despite of numerous experimental studies of the plastic stent occlusion, the optimal period for the device replacement is still unknown. Too frequent stent exchange may lead to additional complications, so the patient-specific approach of stent clogging is necessary. The paper presents a model of lithogenic bile flow as a non-Newtonian fluid with account of transport of particles (cholesterol, bilirubin, calcium) responsible for accumulation at inner stent surface leading to the lumen decrease. The correlation between biliary sludge concentration and clogging time was revealed by designed numerical iteration procedure. The lumen decrease during stent clogging was simulated. Velocity and wall shear stress distribution was found for different sizes of stents. In a stent with a radius of 2 mm in the presence of 59.0% stenosis, the flow velocity reaches 1.05 cm/s in the narrowest part. Wall shear stress is equal to 1.15 Pa. The effect of age, sex, viscosity, biliary sludge concentration and stent radius on the clogging time was evaluated.


Series on Biomechanics, Vol.33, No.1 (2019), 3-15

Keywords: Bile; biliary stent; non-Newtonian fluid; particle transport modelling; stent clogging

Date published: 2019-04-24