For the diagnosis and management of Coronary Artery Disease, the current clinical practice involves assessment of the diseased vessel by Quantitative Coronary Angiography (QCA). Such an assessment provides the clinician with a rich anatomical overview of the stenosis segment, including the area reduction, but does not provide a functional assessment. FFR values (measured by introducing a pressure wire in the stenosed vessel) is the current state-of-the-art technique for the functional assessment of the stenosis [Pijls et al. 2009]. QCA only evaluates the morphological significance of the stenosis and has a series of other limitations, pressure-wire based FFR involves risks associated with the intervention and for very narrow stenoses the pressure wire may induce an additional pressure drop [Pijls et al. 2000]. All of these shortcomings are eliminated through the approach proposed by us and by using a state-of-the-art multi-scale approach accelerated through high-performance activities the usual time-limitation imposed by CFD based simulations is eliminated. Previous CFD-based simulations of the coronary tree have used exclusively 3D modeling [Kim et al. 2010], thus leading to high computational complexities, coupled with simple heart models, which can not include all patient-specific aspects like local movement of the heart. Other approaches have included only 1D modeling (also coupled with a simple heart model) [van der Horst 2011], leading to difficulties in assessing the pressure-drop along the stenosis, since the exact shape of the stenosis was not included considered.

Overall, our proposed model will considerably advance the current state-of-the-art modeling for coronary circulation, by efficiently coupling individual models at different levels, most of which are currently the most advanced models for their individual context. As discussed in previous sections. we will use both 3D and 1D models for coronary circulation at the organ level, and couple them with a state-of the-art full heart model (which includes anatomy, dynamics and hemodynamics), while the computational complexity will be addressed through the high performance activities.

In addition to the diagnosis, we also propose to use the validated multi-scale models as a planning tool for virtual interventions. Though there has been previous work on virtual interventions on coronaries, none of them have used the comprehensive multi-scale models for coronary circulation.