In vivo validation of a one-dimensional finite-element method for predicting blood flow in cardiovascular bypass grafts

Abstract

Current practice in vascular surgery utilizes only diagnostic and empirical data to plan treatments and does not enable quantitative a priori prediction of the outcomes of interventions. We have previously described a new approach to vascular surgery planning based on solving the governing equations of blood flow in patient-specific models. A one-dimensional finite-element method was used to simulate blood flow in eight porcine thoraco-thoraco aortic bypass models. The predicted flow rate was compared to in vivo data obtained using cine phase-contrast magnet resonance imaging. The mean absolute difference between computed and measured flow distribution in the stenosed aorta was found to be 4.2% with the maximum difference of 10.6% anda minimum difference of 0.4%. Furthermore, the sensitivity of the flow rate and distribution with respect to stenosis and branch losses were quantified.

Non-Invasive Hemodynamic Assessment of Aortic Coarctation: Validation with In Vivo Measurements

“…To build the descretized geometric mesh from the centerline and cross-sectional areas, we used an approach similar to previously introduced ones 21 , wherein for each vessel of the arterial model, we used several distinct 1D segments with spatially varying cross-sectional area values in order to obtain a geometry close to the 3D geometry acquired through MRI. The solution at the interface locations between the separate 1D segments was determined by considering continuity of flow rate and total pressure, similarly to bifurcation solutions ( (4) and (5)).…”

“…The turbulent term has been successfully used in different, independent studies performed in-vitro 19 and in-vivo 21 . We also included a continuous term, which has been introduced previously 2 as a result of the phase difference between the flow rate and the pressure drop identified in a computational study.…”

Geometric multiscale modeling of the cardiovascular system, between theory and practice

“…This simple law, stating that the membrane radial displacement η r is linearly proportional to the fluid pressure, is successfully considered in many applications, see, e.g., [80,118,181]. Other laws have been proposed to account for other features of the arterial wall.…”

“…The accuracy of the solution provided by the 1D model is addressed in several works. Among them, we cite [7], where a network of 128 vessels is considered for the description of the whole system, and the numerical results have been compared successfully with measurements taken in the ascending aorta, descending aorta, brachiocephalic and right common iliac arteries; [181], where the numerical results obtained in aorta are shown to be in good agreement with MRI measurements; [118,128], where a comparison with in vitro measurements is performed for a complete network of the system; [169], where a comparison with clinical measurements is addressed, with a particular focus on the circle of Willis; [181], where a validation is presented for the case of a by-pass graft.…”

Viscoelastic Mapping of the Arterial Ovine System using a Kelvin Model

“…Thus, if a more advanced viscoelastic wall mechanics model can be developed, it may be of interest to researchers developing fluid dynamic models, particularly if the wall mechanics model can be easily integrated into the fluid solver. At present, most fluid mechanics models (e.g., [14], [15], [16], [17], [18], [19], [20], [21], [22]), assume either that arteries are rigid or exhibit a purely elastic response. While more recent studies [23], [24], [25], [26], have accounted for viscoelastic properties, they have not incorporated variations in wall properties at different locations in the network.…”