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Particle image velocimetry of coronary flow

Pedro Garcia Carrascal, Javier Garcia, Jose Sierra Pallares, Francisco Castro Ruiz, Fernando Manuel Martín
In-stent restenosis ails many patients who have undergone stenting. When the stented artery is a bifurcation, the intervention is especially critical because of the complex stent geometry involved in these structures. Computational Fluid Dynamics (CFD) has demonstrated to be an effective approach when modelling blood flow behavior and understanding the mechanisms that underlie in-stent restenosis. These CFD models, however, require validation through experimental data in order to be reliable. It is with this purpose in mind that we performed Particle Image Velocimetry (PIV) measurements of velocity fields within flows through a simplified coronary bifurcation...
March 22, 2018: Journal of Biomechanical Engineering
Hoda Hatoum, Jennifer Dollery, Scott M Lilly, Juan A Crestanello, Lakshmi Prasad Dasi
BACKGROUND: This study aims to evaluate the effect of transcatheter aortic valve (TAV) implantation depth and rotation on pressure gradient (PG), leakage fractions (LF), leaflet shear stress and sinus washout in an effort to understand factors that may dictate optimal positioning for valve-in-valve (ViV) procedures. Sinus flow stasis is often associated with prosthetic leaflet thrombosis. While recent ViV in-vitro studies highlighted transcatheter aortic valve (TAV) supra-annular implantation potential benefits to minimize pressure gradients, the relationship between TAV depth and other determinates of valve function remains unknown...
March 1, 2018: Annals of Thoracic Surgery
Rodward L Hewlin, John P Kizito
The ultimate goal of the present work is to aid in the development of tools to assist in the treatment of cardiovascular disease. Gaining an understanding of hemodynamic parameters for medical implants allow clinicians to have some patient-specific proposals for intervention planning. In the present work an experimental and digital computational fluid dynamics (CFD) arterial model consisting of a number of major arteries (aorta, carotid bifurcation, cranial, femoral, jejunal, and subclavian arteries) were fabricated to study: (1) the effects of local hemodynamics (flow parameters) on global hemodynamics (2) the effects of transition from bedrest to upright position (postural change) on hemodynamics, and (3) diffusion of dye (medical drug diffusion simulation) in the arterial system via experimental and numerical techniques...
March 2018: Cardiovascular Engineering and Technology
Hoda Hatoum, Brandon L Moore, Pablo Maureira, Jennifer Dollery, Juan A Crestanello, Lakshmi Prasad Dasi
OBJECTIVE: Valve-in-valve procedures using transcatheter aortic valves are increasingly performed to treat degenerated bioprosthetic surgical aortic valves because they are less invasive than redo aortic valve replacement. The objective of this study is to quantify the changes in aortic sinus blood flow dynamics before and after a valve-in-valve procedure to gain insight into mechanisms for clinical and subclinical thrombosis of leaflets. METHODS: A detailed description of the sinus hemodynamics for valve-in-valve implantation was performed in vitro...
July 2017: Journal of Thoracic and Cardiovascular Surgery
Andrew McNally, Ashish Madan, Philippe Sucosky
The bicuspid aortic valve (BAV) is a major risk factor for secondary aortopathy such as aortic dilation. The heterogeneous BAV morphotypes [left-right-coronary cusp fusion (LR), right-non-coronary cusp fusion (RN), and left-non-coronary cusp fusion (LN)] are associated with different dilation patterns, suggesting a role for hemodynamics in BAV aortopathogenesis. However, assessment of this theory is still hampered by the limited knowledge of the hemodynamic abnormalities generated by the distinct BAV morphotypes...
2017: Frontiers in Physiology
Elizabeth E Antoine, François P Cornat, Abdul I Barakat
Although vascular disease is a leading cause of mortality, in vitro tools for controlled, quantitative studies of vascular biological processes in an environment that reflects physiological complexity remain limited. We developed a novel in vitro artery that exhibits a number of unique features distinguishing it from tissue-engineered or organ-on-a-chip constructs, most notably that it allows deployment of endovascular devices including stents, quantitative real-time tracking of cellular responses and detailed measurement of flow velocity and lumenal shear stress using particle image velocimetry...
December 2016: Journal of the Royal Society, Interface
Melissa C Brindise, Claudio Chiastra, Francesco Burzotta, Francesco Migliavacca, Pavlos P Vlachos
Stent implantation in coronary bifurcations presents unique challenges and currently there is no universally accepted stent deployment approach. Despite clinical and computational studies, the effect of each stent implantation method on the coronary artery hemodynamics is not well understood. In this study the hemodynamics of stented coronary bifurcations under pulsatile flow conditions were investigated experimentally. Three implantation methods, provisional side branch (PSB), culotte (CUL), and crush (CRU), were investigated using time-resolved particle image velocimetry to measure the velocity fields...
March 2017: Annals of Biomedical Engineering
Gautam Kumar, Vrishank Raghav, Stamatios Lerakis, Ajit P Yoganathan
BACKGROUND AND AIM OF THE STUDY: Transcatheter aortic valve replacements (TAVRs) are performed using fluoroscopic guidance, which makes precise positioning challenging. The aim of the present study was to investigate the effect of TAV positioning on flow characteristics in the ascending aorta and sinuses. METHODS: A commonly used TAV design with a supra-annular support section was investigated using particle image velocimetry (PIV) under physiological flow and pressure conditions...
January 2015: Journal of Heart Valve Disease
Brandon L Moore, Lakshmi Prasad Dasi
Mechanical stresses on aortic valve leaflets are well-known mediators for initiating processes leading to calcific aortic valve disease. Given that non-coronary leaflets calcify first, it may be hypothesized that coronary flow originating from the ostia significantly influences aortic leaflet mechanics and sinus hemodynamics. High resolution time-resolved particle image velocimetry (PIV) measurements were conducted to map the spatiotemporal characteristics of aortic sinus blood flow and leaflet motion with and without physiological coronary flow in a well-controlled in vitro setup...
September 2015: Annals of Biomedical Engineering
Jaime S Raben, Stefano Morlacchi, Francesco Burzotta, Francesco Migliavacca, Pavlos P Vlachos
PURPOSE: Despite the atheroprone environment of blood flow in coronary bifurcations, limited quantitative information is available on the hemodynamics occurring in these geometries, both before and after their treatment with endovascular stents. Previous studies have focused on computational fluid dynamics (CFD) analyses and have bypassed the challenges associated with experimentally representing the flow environment, providing no means for validation. This study analyzed steady flow conditions in 3 bifurcation angles and 4 different single- and double-stenting procedures, which are used clinically in coronary bifurcations...
July 4, 2015: Journal of Applied Biomaterials & Functional Materials
Foad Kabinejadian, Dhanjoo N Ghista, Boyang Su, Mercedeh Kaabi Nezhadian, Leok Poh Chua, Joon Hock Yeo, Hwa Liang Leo
This study documents the superior hemodynamics of a novel coupled sequential anastomoses (SQA) graft design in comparison with the routine conventional end-to-side (ETS) anastomoses in coronary artery bypass grafts (CABG). The flow fields inside three polydimethylsiloxane (PDMS) models of coronary artery bypass grafts, including the coupled SQA graft design, a conventional ETS anastomosis, and a parallel side-to-side (STS) anastomosis, are investigated under pulsatile flow conditions using particle image velocimetry (PIV)...
October 2014: Medical Engineering & Physics
Clara Seaman, A George Akingba, Philippe Sucosky
The bicuspid aortic valve (BAV), which forms with two leaflets instead of three as in the normal tricuspid aortic valve (TAV), is associated with a spectrum of secondary valvulopathies and aortopathies potentially triggered by hemodynamic abnormalities. While studies have demonstrated an intrinsic degree of stenosis and the existence of a skewed orifice jet in the BAV, the impact of those abnormalities on BAV hemodynamic performance and energy loss has not been examined. This steady-flow study presents the comparative in vitro assessment of the flow field and energy loss in a TAV and type-I BAV under normal and simulated calcified states...
April 2014: Journal of Biomechanical Engineering
Ashkan Javadzadegan, Yasutomo Shimizu, Masud Behnia, Makoto Ohta
BACKGROUND: Flow recirculation and shear strain are physiological processes within coronary arteries which are associated with pathogenic biological pathways. Distinct Quite apart from coronary stenosis severity, lesion eccentricity can cause flow recirculation and affect shear strain levels within human coronary arteries. OBJECTIVE: The aim of this study is to analyse the effect of lesion eccentricity on the transient flow behaviour in a model of a coronary artery and also to investigate the correlation between Reynolds number (Re) and the eccentricity effect on flow behaviour...
2013: Technology and Health Care: Official Journal of the European Society for Engineering and Medicine
Konstantinos Lampropoulos, Werner Budts, Alexander Van de Bruaene, Els Troost, Joost P van Melle
No abstract text is available yet for this article.
April 26, 2012: Cardiovascular Ultrasound
Amal Ahmed Owida, Hung Do, Yos S Morsi
Arterial bypass grafts tend to fail after some years due to the development of intimal thickening (restenosis). Non-uniform hemodynamics following a bypass operation contributes to restenosis and bypass failure can occur due to the focal development of anastomotic intimal hyperplasia. Additionally, surgical injury aggravated by compliance mismatch between the graft and artery has been suggested as an initiating factor for progress of wall thickening along the suture line Vascular grafts that are small in diameter tend to occlude rapidly...
November 2012: Computer Methods and Programs in Biomedicine
Breigh N Roszelle, Steven Deutsch, William J Weiss, Keefe B Manning
The aim of this study is to define the fluid mechanics of a pulsatile pneumatically driven pediatric ventricular assist device (PVAD), for the reduced flow rates encountered during device weaning and myocardial recovery, and relate the results to the potential for thromboembolic events. We place an acrylic model of the PVAD in a mock circulatory loop filled with a viscoelastic blood analog and operate at four stroke volumes (SVs), each with two different filling conditions, to mimic how the flow rate of the device may be reduced...
July 2011: Annals of Biomedical Engineering
Chris Hutchison, Pierre Sullivan, C Ross Ethier
Computational modeling of bileaflet mechanical heart valve (BiMHV) flow requires experimentally validated datasets and improved knowledge of BiMHV fluid mechanics. In this study, flow was studied downstream of a model BiMHV in an axisymmetric aortic sinus using stereoscopic particle image velocimetry. The inlet flow was steady and the Reynolds number based on the aortic diameter was 7600. Results showed the out-of-plane velocity was of similar magnitude as the transverse velocity. Although additional studies are needed for confirmation, analysis of the out-of-plane velocity showed the possible presence of a four-cell streamwise vortex structure in the mean velocity field...
March 2011: Medical & Biological Engineering & Computing
Damien Garcia, Juan C Del Alamo, David Tanne, Raquel Yotti, Cristina Cortina, Eric Bertrand, José Carlos Antoranz, Esther Perez-David, Régis Rieu, Francisco Fernandez-Aviles, Javier Bermejo
Doppler echocardiography remains the most extended clinical modality for the evaluation of left ventricular (LV) function. Current Doppler ultrasound methods, however, are limited to the representation of a single flow velocity component. We thus developed a novel technique to construct 2D time-resolved (2D+t) LV velocity fields from conventional transthoracic clinical acquisitions. Combining color-Doppler velocities with LV wall positions, the cross-beam blood velocities were calculated using the continuity equation under a planar flow assumption...
October 2010: IEEE Transactions on Medical Imaging
Satyaprakash Karri, Pavlos P Vlachos
The effect of phase angle between pressure and flow waveforms on the flow characteristics in stenosed compliant vessels for coronary (phase angle (PA) of approximately -225 deg) and peripheral flows (PA of approximately -45 deg) is investigated using time resolved digital particle image velocimetry. Synthetic arteries with 50% and 75% stenosis at various physiological conditions with Reynolds numbers (Re) of 250, 350, and 450 and corresponding Womersley parameter (alpha) of 2.7, 3.2, and 3.7 were studied; wall-shear stresses (WSSs), oscillatory shear index (OSI), and recirculation lengths were determined...
March 2010: Journal of Biomechanical Engineering
John Charonko, Satyaprakash Karri, Jaime Schmieg, Santosh Prabhu, Pavlos Vlachos
Time resolved particle image velocimetry was used to measure wall shear stress (WSS) and oscillatory shear index (OSI) within a 3.0 mm diameter compliant vessel model implanted with an Abbott Vascular XIENCE V stent in five configurations: baseline, over-expanded, increased vessel diameter, two overlapped stents, and increased stent length. Flow through unstented vessels was also tested for comparison. Flow conditions featured a realistic coronary pressure-flow offset and reversal at average flow rates corresponding to resting (Re=160, f=70 bpm) and exercise conditions (Re=300, f=120 bpm)...
March 2010: Annals of Biomedical Engineering
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