The project "Optimisation of a Left Ventricular Assist Device Cannula", delivered for Medical Simulation Technologies Ltd in 2015, addressed a practical healthcare challenge through computational fluid dynamics (CFD). Rather than producing simulation images in isolation, the study was organised around the client's design questions: what controlled performance, where the principal risks or losses occurred, and how the design or operating strategy could be improved.

Heart failure is the leading cause of hospitalisation in people over 65. A left ventricular assist device (LVAD) is an option to provide mechanical circulatory support as a ‘bridge to cardiac transplantation’ or ‘destination therapy’. The aim of this project was to assess the effects of different LVAD connection on the blood flow in order to find the optimum cannula connection. The other aim of this work was to assess the effects of LVAD on the severity of heart failure. In this project, a patient specific configuration, obtained by MRI was converted into a computational model and accurate CFD simulations were carried out for different degree of heart failure. This project resulted in important findings about the surgical configuration and the design of LVAD cannulas.

The methodology centred on a patient-specific cardiovascular CFD model reconstructed from MRI and extended to include alternative LVAD cannula connections. The representation retained the ventricle, aorta, graft and anastomosis regions where cannula position and angle control jet direction, mixing and wall loading. Boundary and operating conditions covered different degrees of heart failure, clinically relevant flow splits and alternative surgical connection geometries, with material, fluid and equipment properties assigned from the available design information. Resolution was concentrated in regions where steep velocity, thermal, concentration or phase gradients were expected, while the overall model remained efficient enough to compare several credible configurations. This balance allowed system-level performance to be linked to the local mechanisms responsible for it.

The assessment compared cannula orientation, insertion position and anastomosis configuration. Performance was judged using flow distribution, pressure, jet impingement, recirculation, wall shear, stagnation and the haemodynamic interaction between native and assisted flow. Results were reviewed through quantitative summaries and engineering visualisations, such as contours, vectors, streamlines, sections and time histories, selected to suit the physics. Important assumptions and operating uncertainties were considered so that the recommendations relied on repeatable comparative trends rather than a single nominal case.

For Medical Simulation Technologies Ltd, the principal value was design and surgical guidance for selecting cannula arrangements with more favourable haemodynamics. The final evidence linked each recommendation to the relevant model or process output, making it suitable for internal design reviews, supplier or contractor discussions and, where applicable, planning, safety or regulatory dialogue. The work also created a reusable baseline that can be updated as geometry, operating data or test results become available, reducing the cost and risk of later design iterations.

A disciplined quality-control workflow supported the analysis. Geometry, units, mass and energy balances, boundary-condition consistency and solver convergence were checked before options were ranked. Mesh or parameter sensitivities were used where they were most likely to affect the engineering conclusion, and limitations were documented explicitly. This ensured that the study remained traceable and reproducible rather than relying on isolated simulation images.