Global Sensitivity Analysis of Four Chamber Heart Hemodynamics Using Surrogate Models

Abstract

Computational Fluid Dynamics (CFD) is used to assist in designing artificial valves and planning procedures, focusing on local flow features. However, assessing the impact on overall cardiovascular function or predicting longer-term outcomes may requires more comprehensive whole heart CFD models. Fitting such models to patient data requires numerous computationally expensive simulations, and depends on specific clinical measurements to constrain model parameters, hampering clinical adoption. Surrogate models can help to accelerate the fitting process while accounting for the added uncertainty. We create a validated patient-specific four-chamber heart CFD model based on the Navier-Stokes-Brinkman (NSB) equations and test Gaussian Process Emulators (GPEs) as a surrogate model for performing a variance-based global sensitivity analysis (GSA). GSA identified preload as the dominant driver of flow in both the right and left side of the heart, respectively. Left-right differences were seen in terms of vascular outflow resistances, with pulmonary artery resistance having a much larger impact on flow than aortic resistance. Our results suggest that GPEs can be used to identify parameters in personalized whole heart CFD models, and highlight the importance of accurate preload measurements.

A comprehensive and biophysically detailed computational model of the whole human heart electromechanics

“…Computational models of the cardiac function are progressively increasing their role in cardiology, revealing diagnostic information, contributing to the development of new therapies and promising patient-specific treatments based on individual pathophysiology [4][5][6]. Successful examples can be found in the context of cardiac electrophysiology [7][8][9][10][11], electromechanics [12][13][14][15][16] and fluid-dynamics [17][18][19][20].…”

A mathematical model that integrates cardiac electrophysiology, mechanics, and fluid dynamics: Application to the human left heart

“…We remark that we are imposing the same pressure on all pulmonary vein inlets. Although this approach is common in the cardiac modeling literature, 4,40,69 different pressures at the different pulmonary veins could be imposed through suitable modifications of the lumped parameter model.…”

“…While in‐vivo measuring techniques allow to inspect and quantify the heart function and dysfunction, these measures often lack resolution or accuracy, and may be invasive. Mathematical models for computational medicine can provide tools to simulate the human heart function, complementing experimental measurements, providing further insight into the cardiac function, and assisting in the development of personalized treatments 2–7 …”

“…Most of them focus on some specific feature of the heart function, by surrogating the remaining ones with models of reduced dimensionality: electrophysiology, [13][14][15][16][17][18][19][20] cardiac mechanics and electromechanics 2,[21][22][23][24][25][26][27][28][29][30][31][32][33] or computational fluid dynamics (CFD) of the blood. 4,[34][35][36][37][38][39][40][41][42][43] Only few works also consider the interplay between hemodynamics and cardiac mechanics in a fluid-structure interaction (FSI) framework, [44][45][46][47][48] while neglecting or simplifying the electrical processes generating the contraction. [49][50][51][52] Albeit each of the above-mentioned models can provide meaningful insight into the cardiac function in both healthy and pathological conditions, they often neglect the feedback mechanisms that relate the different components.…”

An electromechanics-driven fluid dynamics model for the simulation of the whole human heart

“…Thus, FSI valve models are commonly associated to a huge computational burden, to be added to the overall cost of the heart CFD simulation. To avoid this large computational cost, the effects of the valves in the blood can be surrogated by relying on reduced models for the valve dynamics [5,34,47,[71][72][73][74].…”