A MODIFIED WINDKESSEL MODEL APPLIED IN A TUBULAR PULSATION DAMPENER ANALYSIS

2021 ◽  
Author(s):  
Michel de Oliveira dos Santos ◽  
Daniel Ribeiro ◽  
João Paulo Barbosa ◽  
Renato Siqueira
Keyword(s):  
Windkessel Model

Evaluation of the Circulatory Dynamics by using the Windkessel Model in Different Body Positions

2011 ◽  
Vol 131 (1) ◽  
pp. 140-145
Author(s):  
Kiyoshi Kotani ◽  
Fumiaki Iida ◽  
Yutaro Ogawa ◽  
Kiyoshi Takamasu ◽  
Yasuhiko Jimbo
Keyword(s):  
Windkessel Model ◽  
Circulatory Dynamics

scholarly journals The effect of beta-blockers on hemodynamic parameters in patient-specific blood flow simulations of type-B aortic dissection: a virtual study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Amin Abazari ◽  
Deniz Rafieianzab ◽  
M. Soltani ◽  
Mona Alimohammadi
Keyword(s):  
Aortic Dissection ◽  
Clinical Decision Making ◽  
Beta Blockers ◽  
False Lumen ◽  
Specific Treatment ◽  
Left Ventricular ◽  
Patient Specific ◽  
Type B ◽  
Windkessel Model ◽  
Computed Tomography Images

AbstractAortic dissection (AD) is one of the fatal and complex conditions. Since there is a lack of a specific treatment guideline for type-B AD, a better understanding of patient-specific hemodynamics and therapy outcomes can potentially control the progression of the disease and aid in the clinical decision-making process. In this work, a patient-specific geometry of type-B AD is reconstructed from computed tomography images, and a numerical simulation using personalised computational fluid dynamics (CFD) with three-element Windkessel model boundary condition at each outlet is implemented. According to the physiological response of beta-blockers to the reduction of left ventricular contractions, three case studies with different heart rates are created. Several hemodynamic features, including time-averaged wall shear stress (TAWSS), highly oscillatory, low magnitude shear (HOLMES), and flow pattern are investigated and compared between each case. Results show that decreasing TAWSS, which is caused by the reduction of the velocity gradient, prevents vessel wall at entry tear from rupture. Additionally, with the increase in HOLMES value at distal false lumen, calcification and plaque formation in the moderate and regular-heart rate cases are successfully controlled. This work demonstrates how CFD methods with non-invasive hemodynamic metrics can be developed to predict the hemodynamic changes before medication or other invasive operations. These consequences can be a powerful framework for clinicians and surgical communities to improve their diagnostic and pre-procedural planning.

Electronically Tunable Realization of the Three-Element Arterial Windkessel Model

2021 ◽  
Author(s):  
Kleoniki Baxevanaki ◽  
Stavroula Kapoulea ◽  
Costas Psychalinos ◽  
Ahmed S. Elwakil
Keyword(s):  
Windkessel Model ◽  
Electronically Tunable

Hydrodynamic Evaluation of a Minimally Invasive Heart Valve in an Isolated Aortic Root Using a Modified In Vitro Model

2009 ◽  
Vol 3 (1) ◽  
Author(s):  
Qiang Wang ◽  
Fernando Jaramillo ◽  
Yasushi Kato ◽  
Leonard Pinchuk ◽  
Richard T. Schoephoerster
Keyword(s):  
Heart Valve ◽  
Aortic Root ◽  
Hydrodynamic Performance ◽  
Average Pressure ◽  
Left Heart ◽  
Windkessel Model ◽  
Combination Device ◽  
Hydrodynamic Evaluation ◽  
Average Pressure Gradient ◽  
Total Compliance

Implantation methods for commercially available heart valve prostheses require open-chest access to the heart to perform the suturing process. In order to alleviate this complicated surgical implant technique, a “stent-valve” design was developed that will provide a less cumbersome implantation method and therefore a less invasive access to the heart. The purpose of this study is to verify its hydrodynamic performance and migration characteristics to assess its feasibility for use as a replacement heart valve. Hydrodynamic evaluation of the novel stent-valve combination device was carried out using a Vivitro left heart simulator and by setting up a comparison with the same 19 mm trileaflet valve under a traditional implantation (suture) method. To assess implantation ability under normal physiological conditions, porcine aortic root tissue was mounted into the left heart simulator to replace the original glass sinus. A comparison experiment was conducted to study the change in the total compliance and resistance of the testing system using the modified Windkessel model. For the range of test conditions investigated, the stent-valve combination device produced an average pressure gradient of 41.2 mm Hg(±19.6 mm Hg), an average effective orifice area (EOA) of 1.06 cm2(±0.08 cm2), and an average regurgitation percentage of 4.5% (±3.3%), while the sutured valve produced an average pressure gradient of 48.7 mm Hg(±17.4 mm Hg), an average EOA of 0.88 cm2(±0.14 cm2), and an average regurgitation percentage of 0.8% (±0.4%). The total compliance and resistance of the system was 0.37 ml/mm Hg(±0.01 ml/mm Hg) and 1.1 mm Hg/ml/s(±0.29 mm Hg/ml/s), with the original Windkessel model, and 0.33 ml/mm Hg(±0.01 ml/mm Hg) and 1.1 mm Hg/ml/s(±0.24 mm Hg/ml/s) for the system with the aortic tissue. The stent-valve combination device has demonstrated favorable hydrodynamic performance when compared with the same trileaflet valve under the traditional suturing method, and the arterial stent makes it possible to secure the valve at its required position without migration.

Dynamics of cerebral blood flow regulation explained using a lumped parameter model

2002 ◽  
Vol 282 (2) ◽  
pp. R611-R622 ◽  
Author(s):  
Mette S. Olufsen ◽  
Ali Nadim ◽  
Lewis A. Lipsitz
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cardiovascular Response ◽  
Lumped Parameter Model ◽  
Initial Increase ◽  
Windkessel Model ◽  
Cerebrovascular Resistance ◽  
Posture Change ◽  
Lumped Parameter ◽  
Young Subjects

The dynamic cerebral blood flow response to sudden hypotension during posture change is poorly understood. To better understand the cardiovascular response to hypotension, we used a windkessel model with two resistors and a capacitor to reproduce beat-to-beat changes in middle cerebral artery blood flow velocity (transcranial Doppler measurements) in response to arterial pressure changes measured in the finger (Finapres). The resistors represent lumped systemic and peripheral resistances in the cerebral vasculature, whereas the capacitor represents a lumped systemic compliance. Ten healthy young subjects were studied during posture change from sitting to standing. Dynamic variations of the peripheral and systemic resistances were extracted from the data on a beat-to-beat basis. The model shows an initial increase, followed approximately 10 s later by a decline in cerebrovascular resistance. The model also suggests that the initial increase in cerebrovascular resistance can explain the widening of the cerebral blood flow pulse observed in young subjects. This biphasic change in cerebrovascular resistance is consistent with an initial vasoconstriction, followed by cerebral autoregulatory vasodilation.

Ventricular Ejection Simulation with Active Atrium using Windkessel Model

1997 ◽  
Vol 30 (2) ◽  
pp. 25-28
Author(s):  
Maurício dos S. Dutra ◽  
Walter C. de Lima ◽  
Jorge M. Barreto
Keyword(s):  
Ventricular Ejection ◽  
Windkessel Model

Identification of the three-element windkessel model incorporating a pressure-dependent compliance

1995 ◽  
Vol 23 (2) ◽  
pp. 164-177 ◽  
Author(s):  
Angelo Cappello ◽  
Gianni Gnudi ◽  
Claudio Lamberti
Keyword(s):  
Windkessel Model

Tissue perfusability assessment from capillary velocimetry data via the multicompartment Windkessel model

2015 ◽  
Author(s):  
Elena S. Stiukhina ◽  
Maxim A. Kurochkin ◽  
Victor A. Klochkov ◽  
Ivan V. Fedosov ◽  
Dmitry E. Postnov
Keyword(s):  
Windkessel Model

Contribution of arterial Windkessel in low-frequency cerebral hemodynamics during transient changes in blood pressure

2011 ◽  
Vol 110 (4) ◽  
pp. 917-925 ◽  
Author(s):  
Gregory S. H. Chan ◽  
Philip N. Ainslie ◽  
Chris K. Willie ◽  
Chloe E. Taylor ◽  
Greg Atkinson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Goodness Of Fit ◽  
Low Frequency ◽  
Pressure Rise ◽  
Windkessel Model ◽  
Arterial Blood ◽  
Low Pass ◽  
Acute Changes

The Windkessel properties of the vasculature are known to play a significant role in buffering arterial pulsations, but their potential importance in dampening low-frequency fluctuations in cerebral blood flow has not been clearly examined. In this study, we quantitatively assessed the contribution of arterial Windkessel (peripheral compliance and resistance) in the dynamic cerebral blood flow response to relatively large and acute changes in blood pressure. Middle cerebral artery flow velocity (MCAV; transcranial Doppler) and arterial blood pressure were recorded from 14 healthy subjects. Low-pass-filtered pressure-flow responses (<0.15 Hz) during transient hypertension (intravenous phenylephrine) and hypotension (intravenous sodium nitroprusside) were fitted to a two-element Windkessel model. The Windkessel model was found to provide a superior goodness of fit to the MCAV responses during both hypertension and hypotension ( R2 = 0.89 ± 0.03 and 0.85 ± 0.05, respectively), with a significant improvement in adjusted coefficients of determination ( P < 0.005) compared with the single-resistance model ( R2 = 0.62 ± 0.06 and 0.61 ± 0.08, respectively). No differences were found between the two interventions in the Windkessel capacitive and resistive gains, suggesting similar vascular properties during pressure rise and fall episodes. The results highlight that low-frequency cerebral hemodynamic responses to transient hypertension and hypotension may include a significant contribution from the mechanical properties of vasculature and, thus, cannot solely be attributed to the active control of vascular tone by cerebral autoregulation. The arterial Windkessel should be regarded as an important element of dynamic cerebral blood flow modulation during large and acute blood pressure perturbation.

Sign in / Sign up

Export Citation Format

Share Document