Tuning Multidomain Hemodynamic Simulations to Match Physiological Measurements

Abstract

In recent years, considerable progress has been made in creating more realistic models of the cardiovascular system, often based on patient-specific anatomic data, whereas comparatively little progress has been made on incorporating measured physiological data. We have developed a method to systematically adjust the parameters of three-element windkessel outlet boundary conditions of three-dimensional blood flow models such that desired features of pressure and flow waveforms are achieved. This tuning method was formulated as the solution of a nonlinear system of equations and employed a quasi-Newton method that was informed by a reduced-order model. The three-dimensional hemodynamic models were solved using a stabilized finite-element method incorporating deformable vessel walls. The tuning method was applied to an idealized common carotid artery, an idealized iliac arterial bifurcation, and a patient-specific abdominal aorta. The objectives for the abdominal aortic model were values of the maximum and minimum of the pressure waveform, an indicator of the pressure waveform's shape, and the mean, amplitude, and diastolic mean of the flow waveform for an infrarenal measurement plane. The hemodynamic models were automatically generated and tuned by custom software with minimal user input. This approach enables efficient development of cardiovascular models for applications including detailed evaluation of cardiovascular mechanics, simulation-based design of medical devices, and patient-specific treatment planning.

Inverse problems in reduced order models of cardiovascular haemodynamics: aspects of data assimilation and heart rate variability

“…The results of the UKF estimation are presented in figure 10. The evolution of estimate means and variances shows that all parameters are converged and that their variances decrease by a factor of at least 2 5 . A comparison of model output (with UKF-estimated parameters) with the measurements is shown in figure 11.…”

Boundary conditions of patient-specific fluid dynamics modelling of cavopulmonary connections: possible adaptation of pulmonary resistances results in a critical issue for a virtual surgical planning

“…The C tot-r /C tot-l ratio was kept constant and equal to (R tot-r /R tot-l ) 20.75 according to proper scaling rules [18]. Moreover, C tot-r and C tot-l were distributed among the two blocks of the right and left lung models, respectively (C 1r , C 2r and C 1l , C 2l ; table 2), according to the assumed r C .…”

Personalized blood flow computations: A hierarchical parameter estimation framework for tuning boundary conditions

“…Olufsen et al described a calibration method for determining the dynamic cerebral blood flow response to sudden hypotension during posture change [17]. An optimization-based iterative calibration method for the windkessel models was suggested [18], where the input was specified by non-invasively acquired systolic/diastolic pressures and, in some cases, additional flow data. The windkessel parameters were obtained by solving a system of nonlinear equations, formulated based on a set of objectives for the pressure and flow rate waveforms at various locations.…”