Development and personalisation of coupled 3d-1d models of cardiovascular function
A key factor governing the mechanical performance of the heart is the bidirectional coupling with the cardiovascular system where alterations in the arterial system modulate the pulsatile load imposed on the heart. Current image-based computational models of cardiac electro-mechanics (EM) use simplified 0D representations of the vascular system when coupling to anatomically accurate 3D EM models is considered. However, these neglect important effects related to pulse wave transmission. Accounting for these effects requires 1D models, but a 3D-1D coupling remains challenging.
In this talk, we present a novel, stable strategy to couple a 3D cardiac EM model to a 1D model of blood flow in the arterial system. For the first time, a coupled 3D-1D model of left ventricle (LV) and arterial system is built and used in numerical benchmarks to demonstrate robustness and accuracy of our scheme over a range of time steps. Validation of the coupled model is performed by investigating the coupled system’s physiological response to variations in the arterial system affecting pulse wave propagation, comprising aortic stiffening, aortic stenosis or bifurcations causing wave reflections.
In the perspective of clinical translation we also show current advances in the personalisation of the coupled model. First, we present a novel methodology to simultaneously perform an automated identification of in vivo passive mechanical properties and an estimation of the unloaded reference configuration of the left ventricle. Then, we show the results of a preliminary variance-based sensitivity analysis on the novel 3D-1D coupled model. The approach considered is based on the use of Gaussian Process Emulators to construct surrogates of the accurate, high-fidelity coupled model, and efficiently perform sensitivity analysis to characterise the relative importance of model input parameters on the model output.
This work is in collaboration with Dr. Christoph Augustin, Dr. Matthias Gsell, Prof. Gernot Plank, Dr. Justyna Niestrawska, Dr. Laura Marx from the Medical University of Graz and Dr. Jordi Alastruey from King’s College London.
