Coupled Morphological–Hemodynamic Computational Analysis of Type B Aortic Dissection: A Longitudinal Study

Abstract

Progressive false lumen aneurysmal degeneration in type B aortic dissection (TBAD) is a complex process with a multi-factorial etiology. Patient-specific computational fluid dynamics (CFD) simulations provide spatial and temporal hemodynamic quantities that facilitate understanding this disease progression. A longitudinal study was performed for a TBAD patient, who was diagnosed with the uncomplicated TBAD in 2006 and treated with optimal medical therapy but received surgery in 2010 due to late complication. Geometries of the aorta in 2006 and 2010 were reconstructed. With registration algorithms, we accurately quantified the evolution of the false lumen, while with CFD simulations we computed several hemodynamic indexes, including the wall shear stress (WSS), and the relative residence time (RRT). The numerical fluid model included large eddy simulation (LES) modeling for efficiently capturing the flow disturbances induced by the entry tears. In the absence of complete patient-specific data, the boundary conditions were based on a specific calibration method. Correlations between hemodynamics and the evolution field in time obtained by registration of the false lumen are discussed. Further testing of this methodology on a large cohort of patients may enable the use of CFD to predict whether patients, with originally uncomplicated TBAD, develop late complications.

Patient‐specific CFD modelling in the thoracic aorta with PC‐MRI–based boundary conditions: A least‐square three‐element Windkessel approach

“…Using turbulence modelling in this Reynolds range is not strictly necessary, as a fine enough mesh may be sufficient to resolve the velocity field. Recent work incorporated large eddy simulation to model turbulence as a possible strategy for reducing the computational cost in Computer‐Aided Clinical Trials, thanks to the use of coarser reticulations. However, here we choose direct numerical solution of the equations, being the number of simulations to run pretty modest.…”

Patient-specific haemodynamic simulations of complex aortic dissections informed by commonly available clinical datasets

“…However, the calibration of the Windkessel models is not an easy exercise, and different strategies are proposed in the literature. Some strategies adopt only haemodynamic data taken from the literature [8], others make use of patient-specific flow waves integrated with literature-based pressure waves [7], while more advanced approaches use sophisticated techniques such as Kalman filters to assimilate boundary flow waves acquired with PC-MRI [9]. However, relying exclusively on literature data does not lead to the development of accurate personalised models and advanced clinical data, such as PC-MRI data, are not often acquired during routine monitoring.…”

Optimization schemes for endovascular repair with parallel technique based on hemodynamic analyses

“…In fact, there is strong secondary flow occurred in the root of AA; however, this flow pattern may have less effects on the descending aorta and the distal region than the region close to AA . Most studies focused on type‐B aortic dissection neglected it and assigned flat velocity profile at the aortic inlet . The flow rates over a cardiac cycle were calculated from the measured data of 20 volunteers for each velocity boundary.…”