A 3D MULTISCALE MODEL OF THROMBOLYSIS FOR PATIENT-SPECIFIC APPLICATIONS
Andris Piebalgs, Xiao Yun Xu
Imperial College London, UK
Thromboembolic events occur when an abnormal blood clot blocks blood supply to important human organs. This condition can be treated using thrombolytic therapy that dissolves the occluding blood clot via an infusion of a thrombolytic agent. However, in certain scenarios the treatment can be ineffective and cause life-threatening side-effects such as intracerebral haemorrhage. Mathematical modelling can provide insights into the lytic process and suggest possible means to optimise existing therapies. In this abstract, we present the first multiscale model that is capable of predicting the temporal dissolution of occluding clots during thrombolytic therapy in patient-specific geometries.
The occluding blood clot is treated as a fibrous porous medium whose macroscopic properties are determined by evaluating the dissolution of fibrin fibres on the microscale. The kinetics of clot lysis takes into account the reaction of lysis proteins on the clot surface. Blood flow is governed by modified fluid mass and momentum equations while the transport of lysis proteins is described by a set of diffusionconvection-reaction equations. Realistic models of the internal carotid bifurcation are built from medical images to simulate the treatment of ischemic stroke where an occluding blood clot is present in the middle cerebral artery. Physiologically relevant pulsatile flow conditions are applied at the model inlet and outlets.
Results show that detailed flow features are of paramount importance in evaluating clot lysis patterns during thrombolytic therapy. The transient behaviour of blood flow results in localised tPA hotspots that cause the development of an asymmetrical lysis pattern. This leads to the formation of small clot remnants that may detach from the main body of the clot and cause micro-occlusions in the downstream vasculature. Furthermore, the effects of clot properties, location and size have been examined to ascertain their influence on treatment outcome.