Modeling blood flow around a thrombus using a hybrid particle-continuum approach.

A hybrid, multiscale, particle-continuum numerical method is developed for resolving the interaction of a realistic thrombus geometry with unsteady hemodynamics typically occurring within large arteries. The method is based on a discrete particle/element description of the thrombus, coupled to blood flow using a fictitious domain finite element method. The efficacy of the discrete element approach in representing thrombi with arbitrary aggregate morphology and microstructure is demonstrated. The various features of the method are illustrated using a series of numerical experiments with a model system consisting of an occlusion embedded in a channel. The results from these numerical experiments establish that this approach can resolve the complex macroscale flow structures emanating from unsteady hemodynamics interacting with a thrombus. Simultaneously, it can also resolve micromechanical features, and microscale intra-thrombus flow and perfusion. Using a staggering algorithm, the method can further capture hemodynamics around time-varying thrombus manifolds. This is established using a numerical simulation of lysis of an idealized clot. The hybrid particle-continuum description of thrombus-hemodynamics interaction mechanics, and the unified treatment of macroscale as well as microscale flow and transport, renders significant advantages to the proposed method in enabling further investigations of physiological interest in thrombosis within patient-specific settings.