SLMS Academic Careers Office

21.  Analysis of the performance of novel cardiac valve prosthesis: from standard experimental tests to patient-specific computational analyses

Supervisor Pair: Professor Andrew M Taylor and Dr Silvia Schievano
Potential Student’s Home Department: UCL Institute of Cardiovascular Science

Aortic valve replacement through the implantation of a bio-prosthesis is the most common heart valve surgery, and has become the standard of care in elderly patients with aortic valve disease. Recently, novel sutureless bioprosthetic heart valves have been introduced into clinical practice, aiming at reducing the cross-clamp time and the associated blood damage. Results of clinical trials indicated improved outcomes for the patients, together with enhanced hemodynamic properties. Current data cannot explain the improved haemodynamics of sutureless bioprosthetic heart valves over equivalent standard solutions. A comprehensive biomechanical analysis can help in assessing the overall performance of each device by comparing their outcomes. In this context we suggest to perform in vitro tests, combined with in silico analyses and taking into account in vivo measurements in order to include patient-specific conditions.

Within a clinical context, engineering tests will be conducted in three scenarios of increasing complexity and clinical relevance. First, device hydrodynamic performance assessment will be performed according to standard ISO 5840. Specifically certified equipment will be used to perform ISO standard tests to provide information on the fluid mechanical performance of the prostheses. The results of this test will be used as baseline values of the valve performance under standard conditions and as a reference for validation of computational analyses. Second, such simulations will be set-up to replicate the experiments and to introduce patient-specific conditions of a single patient. Computational analyses will involve state-of-art computational fluid-dynamics (CFD) and investigate novel fluid-structure interactions (FSI) techniques. Measurements of pressure difference, opening areas and flow fields will be taken. Finally, in silico analyses will be performed as based on data of twenty patients who underwent different procedures. Hence, echocardiographic data will be translated as boundary conditions of the computational analyses. Results of the simulations will include flow profiles, areas of turbulence, effective orifice area, velocity magnitude, pressure field, and wall shear stress distributions which will help the assessment of the two devices.

This project aims to address the UCL Grand Challenge of Global Health by supporting a safe introduction of a novel, and less invasive, class of devices for the treatment of aortic valve diseases. This study embraces a multidisciplinary approach including engineering and medical expertise. In addition, this research might lead to an optimized use of patient-specific analysis in the context of personalized treatments.