Customized Bypass Grafting via Density-Based Topology Optimization: A Hemodynamic Perspective

The present study proposes a density-based topology optimization model and evaluates its effectiveness in designing an aorto-coronary bypass. Current literature in bypass design often relies on initial guess solutions iteratively refined with numerical simulations. In contrast, our approach eliminates dependence on arbitrary initial configurations by deriving optimal geometry through the minimization of a functional directly linked to the hydrodynamics within the bypass. This functional is formulated to reduce blood energy dissipation and vorticity, thereby mitigating cardiac pressure overload and preventing recirculation zones that could lead to thrombosis.

The study geometry considers an optimization domain placed beside an idealized coronary artery modelled with increasing grades of stenosis. Boundary conditions prescribed at the inlet and outlet of the system are the physiological aortic pressure and the flow rate in a healthy coronary. The optimized bypass shape effectively restores outlet pressure within the vessel to physiological levels. Furthermore, the design adapts to the severity of the coronary stenosis as the optimal diameter and anastomosis angle increase as the occlusion worsens. These results demonstrate that the topology optimization approach properly addresses the physiological challenges of bypass grafting and suggest that, in the future, this methodology could be developed to support clinicians in therapeutic planning, focusing on patient-tailored solutions.