Patient-Specific In-vitro Modeling and Fluid Dynamics Analysis after a Redo Transcatheter Aortic Valve Replacement

We are examining the fluid dynamics features in a patient-specific aorta model after a redo transcatheter aortic valve replacement (TAVR) therapy focusing on coronary artery access using hemodynamic and Particle Image Velocimetry (PIV). Initially, a 26-mm CoreValve (Medtronic) was deployed at two heights (deep and normal) into a patient-specific aortic root model with coronary arteries. The aortic geometry was based on Computed Tomography (CT) data and the chamber was manufactured through a Silicon-casting method. Subsequently, a 23-mm Sapien 3 was deployed in the first CoreValve at two different heights to incorporate the different feasibility of coronary flow. The redo (TAVR) model was tested in a left heart simulator consisting of a pneumatic bladder pump controlled by a LabVIEW program mimicking the physiological condition of 70 beats per minute, and 120/80 mmHg systolic/diastolic, with an averaged cardiac output of 5 L/min. Utilizing a PIV system, the flow field downstream of the redo TAVR, as well as within the left and right coronary arteries was evaluated. Blood flow stasis and coronary obstruction were assessed in detail. Flow measurements in this study provide insights for clinical procedures regarding the redo TAVR based on the anatomy and the cause of the first valve failure.