Numerical modeling of simulated blood flow in idealized composite arterial coronary grafts: Steady state simulations

Politis, A.K.; Stavropoulos, George; Christolis, M.N.; Panagopoulos, Fotis; Vlachos, N. S.; Markatos, N.C.

doi:10.1016/j.jbiomech.2006.05.008

Cited by 63 publications

(35 citation statements)

References 36 publications

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“…For arterial inlets, the inlet velocity profile for the artery was assumed to be pulsatile. 33 The velocity wave form of one full cardiac cycle with a duration of 1.0 s (representing a heart rate of 60 bpm), illustrated in Fig. 2, was discretized into 1000 steps.…”

Section: Computational Fluid Dynamics Modelsmentioning

confidence: 99%

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

Ngoepe

Reddy

Kahn

et al. 2011

Cardiovasc Eng Tech

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The anastomotic angle is assumed to affect the performance of arterio-venous (AV) access grafts by altering wall shear stress (WSS) and wall tension. The objective of this study was to develop a coupled numerical tool to assess fluid and structural anastomotic mechanics of a straight upper arm access graft. 3D computational fluid dynamics (CFD) and finite element (FE) models were developed for arterial and venous anastomoses with different graft attachment angles. The fluid simulations were executed using flow velocity profiles for anastomotic inlets obtained from a whole-graft CFD model. A mesh adaptation algorithm was developed to couple CFD and FE meshes and capture fluid structure interactions. The coupling algorithm enabled transfer of blood pressure (BP) and WSS predicted with the CFD models to the FE models as loadings. The deformations induced in the FE models were used to update the CFD geometries after which BP and WSS were recalculated and the process repeated until equilibrium between fluid and solid models. Maximum BP in the vein was 181 mmHg. WSS peaked at 2.3 and 0.7 Pa and the structural wall stress reached 3.38 and 3.36 kPa in arterial and venous anastomosis. Since flow-induced wall tension has been identified as a contributor to access graft failure along with WSS, the computational tool will be useful in studying the coupled mechanics in these grafts. Initial investigations of arterial and venous anastomotic end-to-side configuration indicated a slightly better performance of the 90°configuration over 135°a rterial and 45°venous configurations.

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Section: Computational Fluid Dynamics Modelsmentioning

confidence: 99%

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

Ngoepe

Reddy

Kahn

et al. 2011

Cardiovasc Eng Tech

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“…A possible disadvantage of the proposed helical type graft includes the predication of an increased pressure drop, revealing increased flow resistance at a fixed flow rate that results in increased blood pressure, which may facilitate the development and progression of IH and thrombosis [23]. In order analyze the effects of helical bypass on the pressure drop, three bypass graft models were chosen for calculation of area-averaged pressures at two moments: a) first (systolic) peak, as shown in Figure 4(a); b) maximum velocity of the cardiac cycle, measured by the second (diastolic) peak as shown in Figure 4(b).…”

Section: Discussionmentioning

confidence: 99%

Helical type coronary bypass graft performance: Experimental investigations

Bernad

Bosioc

Bernad

et al. 2015

BME

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Abstract. Optimal graft design has been an objective of many researchers to find correlations between hemodynamics and graft failure. Compared to planar grafts, the helical graft configurations improve hemodynamic performance including the promotion of flow mixing and reduction of flow stagnation regions. In order to evaluate the advantages and disadvantages of the suggested helical type bypass graft model in comparison to a conventional bypass graft configuration, three experimental models were designed and evaluated. The character of complex vortex structures created in the area between the heel and the occluded section depends on the flow parameters (in the case of the straight graft). We have identified two vortices in the symmetrical plane (proximal and distal to the anastomosis). In the new design of the two-turn helical graft, the stagnation point is eliminated from the anastomoses at different time intervals compared to the conventional straight bypass model The present study indicated that the magnitude of the pressure drop along a helical graft was considerably increased compared to a traditional graft which, while still physiologically advantageous, can be surpassed by an optimal geometry model.

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“…Idealized parametric cardiovascular models have been successfully employed as a first approximation where 3D morphological and physiological data is incomplete and difficult to acquire (Liu et al,, 2004;Politis et al, 2007). Fetal hemodynamics is one such set of conditions.…”

Section: Discussionmentioning

confidence: 99%

In vitro hemodynamic investigation of the embryonic aortic arch at late gestation

Pekkan

Dasi

Nourparvar

et al. 2008

Journal of Biomechanics

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This study focuses on the dynamic flow through the fetal aortic arch driven by the concurrent action of right and left ventricles. We created a parametric pulsatile computational fluid dynamics (CFD) model of the fetal aortic junction with physiologic vessel geometries. To gain a better biophysical understanding an in vitro experimental fetal flow loop for flow visualization was constructed for identical CFD conditions. CFD and in vitro experimental results were comparable.Swirling flow during the acceleration phase of the cardiac cycle and unidirectional flow following mid-deceleration phase were observed in pulmonary arteries (PA), head-neck vessels, and descending aorta. Right-to-left (oxygenated) blood flowed through the ductus arteriosus (DA) posterior relative to the antegrade left ventricular outflow tract (LVOT) stream and resembled jet flow. LVOT and right ventricular outflow tract flow mixing had not completed until ~3.5 descending aorta diameters downstream of the DA insertion into the aortic arch. Normal arch model flow patterns were then compared to flow patterns of four common congenital heart malformations that include aortic arch anomalies. Weak oscillatory reversing flow through the DA junction was observed only for the Tetralogy of Fallot configuration. Pulmonary Atresia and Hypoplastic Left Heart Syndrome configurations demonstrated complex, abnormal flow patterns in the PAs and head-neck vessels. Aortic Coarctation resulted in large scale recirculating flow in the aortic arch proximal to the DA. Intravascular flow patterns spatially correlated with abnormal vascular structures consistent with the paradigm that abnormal intravascular flow patterns associated with congenital heart disease influence vascular growth and function.

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Numerical modeling of simulated blood flow in idealized composite arterial coronary grafts: Steady state simulations

Cited by 63 publications

References 36 publications

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

A Numerical Tool for the Coupled Mechanical Assessment of Anastomoses of PTFE Arterio-venous Access Grafts

Helical type coronary bypass graft performance: Experimental investigations

In vitro hemodynamic investigation of the embryonic aortic arch at late gestation

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