ONE-DIMENSIONAL SIMULATION OF HAEMODYNAMICS IN AORTIC COARCTATION

Aortic coarctation is a narrowing of part of the aorta due to the congenital defect. It causes abnormally elevated after-load to the left heart and thus impaired blood supply to the peripheral organs. Currently diagnosis and treatment of aortic coarctation are still difficult issues due to the complex haemodynamic changes involved [Keshavarz-Motamed, 2011]. The EU FP7 euHeart project is developing numerical tools to assist clinicians in the diagnostic evaluation of aortic coarctation based on MRI images of patients. The pressure gradient across the aorta in a patient-specific anatomy is computed by 3D computational fluid dynamics, but the result is critically dependent on the balance of the measured ascending aortic flow that is distributed to the supra-aortic vessels and the descending aorta. The balance is achieved using Windkessel models at the four outlets. The process of tuning the Windkessels in combination with the 3D model to match the (noisy) clinical flow measurements is computationally expensive and is sensitive to the initialisation. We propose the use of an intermediate 1D/0D model, based on the geometry of the patient aorta, to pre-tune the system.