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Particle image velocimetry of coronary flow

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https://www.readbyqxmd.com/read/27460012/hemodynamics-of-stent-implantation-procedures-in-coronary-bifurcations-an-in-vitro-study
#1
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...
July 26, 2016: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/26182616/high-transcatheter-valve-replacement-may-reduce-washout-in-the-aortic-sinuses-an-in-vitro-study
#2
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
https://www.readbyqxmd.com/read/25636598/coronary-flow-impacts-aortic-leaflet-mechanics-and-aortic-sinus-hemodynamics
#3
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
https://www.readbyqxmd.com/read/25589159/local-blood-flow-patterns-in-stented-coronary-bifurcations-an-experimental-and-numerical-study
#4
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...
April 2015: Journal of Applied Biomaterials & Functional Materials
https://www.readbyqxmd.com/read/25103345/in-vitro-measurements-of-velocity-and-wall-shear-stress-in-a-novel-sequential-anastomotic-graft-design-model-under-pulsatile-flow-conditions
#5
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
https://www.readbyqxmd.com/read/24474392/steady-flow-hemodynamic-and-energy-loss-measurements-in-normal-and-simulated-calcified-tricuspid-and-bicuspid-aortic-valves
#6
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
https://www.readbyqxmd.com/read/23949178/correlation-between-reynolds-number-and-eccentricity-effect-in-stenosed-artery-models
#7
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
https://www.readbyqxmd.com/read/22537255/correction-visualization-of-the-intracavitary-blood-flow-in-systemic-ventricles-of-fontan-patients-by-contrast-echocardiography-using-particle-image-velocimetry
#8
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
https://www.readbyqxmd.com/read/22217920/numerical-analysis-of-coronary-artery-bypass-grafts-an-over-view
#9
REVIEW
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
https://www.readbyqxmd.com/read/21404124/flow-visualization-of-a-pediatric-ventricular-assist-device-during-stroke-volume-reductions-related-to-weaning
#10
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
https://www.readbyqxmd.com/read/21080093/measurements-of-steady-flow-through-a-bileaflet-mechanical-heart-valve-using-stereoscopic-piv
#11
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
https://www.readbyqxmd.com/read/20562044/two-dimensional-intraventricular-flow-mapping-by-digital-processing-conventional-color-doppler-echocardiography-images
#12
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
https://www.readbyqxmd.com/read/20459198/time-resolved-dpiv-investigation-of-pulsatile-flow-in-symmetric-stenotic-arteries-effects-of-phase-angle
#13
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
https://www.readbyqxmd.com/read/20099035/in-vitro-comparison-of-the-effect-of-stent-configuration-on-wall-shear-stress-using-time-resolved-particle-image-velocimetry
#14
COMPARATIVE STUDY
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
https://www.readbyqxmd.com/read/19381810/in-vitro-time-resolved-piv-comparison-of-the-effect-of-stent-design-on-wall-shear-stress
#15
COMPARATIVE STUDY
John Charonko, Satyaprakash Karri, Jaime Schmieg, Santosh Prabhu, Pavlos Vlachos
The effect of stent design on wall shear stress (WSS) and oscillatory shear index (OSI) was studied in vitro using time-resolved digital particle image velocimetry (DPIV). Four drug-eluting stents [XIENCE V (Abbott Vascular), TAXUS Liberté (Boston Scientific), Endeavor (Medtronic), and Cypher (J&J Cordis)] and a bare-metal stent [VISION (Abbott Vascular)] were implanted into compliant vessel models, and the flow was measured in physiologically accurate coronary conditions featuring reversal and realistic offsets between pressure and flowrate...
July 2009: Annals of Biomedical Engineering
https://www.readbyqxmd.com/read/18604612/dynamic-particle-image-velocimetry-study-of-the-aortic-flow-field-of-contemporary-mechanical-bileaflet-prostheses
#16
Toshinosuke Akutsu, Jun Saito, Ryota Imai, Tomoyuki Suzuki, Xiu Dong Cao
The characteristics of mechanical bileaflet valves, the leaflets of which open at the outside first, differ significantly from those of natural valves, whose leaflets open at the center first, and this fact affects the flow field down-stream of the valves. The direction of jet-type flows, which is influenced by this difference in valve features, and the existence of the sinus of Valsalva both affect the flow field inside the aorta in different ways, depending on the valve design. There may also be an influence on the coronary circulation, the entrance to which resides inside the sinus of Valsalva...
2008: Journal of Artificial Organs: the Official Journal of the Japanese Society for Artificial Organs
https://www.readbyqxmd.com/read/18574310/hemodynamics-altered-by-placing-helix-stents-in-an-aneurysm-at-a-45-degrees-angle-to-the-curved-vessel
#17
Tong-Miin Liou, Yi-Chen Li, Te-Chuan Wang
Flow visualization, particle image velocimetry and numerical computation have been complementarily performed to study the fluid flow inside a stented lateral aneurysm. The curved afferent vessel had an inner diameter of 5 mm. The diameters of the aneurysmal orifice, neck and fundus were 7 mm, 5 mm and 7.5 mm, respectively, and the distance between the orifice and dome measured 10 mm. Stents with various porosities were examined. A volume-flow rate waveform of the internal carotid artery was reconstructed with a Wormersley number of 4 and Reynolds number ranging from 202 to 384 in a cardiac cycle...
July 21, 2008: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/18375587/controlling-cardiac-transport-and-plaque-formation
#18
Ze'ev Aronis, Sagi Raz, Elisha J P Martinez, Shmuel Einav
Macro-particles transported in the bloodstream, such as LDL particles and macrophages, are considered to be one of the initiating factors of atherosclerotic plaque development. LDL infiltration from the bloodstream into a blood vessel's wall, whether the coronary, peripheral, or carotid arteries, is considered a major inflammatory factor, recruiting macrophages from the blood flow and leading to the formation of vulnerable atherosclerotic plaques. Infiltration sites are influenced by patterns of blood flow, as regions of lower shear stresses and high oscillations may give rise to higher infiltration rates through the endothelium, exacerbating the growth of a plaque and its tendency to rupture...
March 2008: Annals of the New York Academy of Sciences
https://www.readbyqxmd.com/read/17466995/piv-validated-numerical-modeling-of-pulsatile-flows-in-distal-coronary-end-to-side-anastomoses
#19
F L Xiong, C K Chong
This study employed particle image velocimetry (PIV) to validate a numerical model in a complementary approach to quantify hemodynamic factors in distal coronary anastomoses and to gain more insights on their relationship with anastomotic geometry. Instantaneous flow fields and wall shear stresses (WSS) were obtained from PIV measurement in a modified life-size silastic anastomosis model adapted from a conventional geometry by incorporating a smooth graft-artery transition. The results were compared with those predicted by a concurrent numerical model...
2007: Journal of Biomechanics
https://www.readbyqxmd.com/read/17320749/left-ventricular-isovolumic-flow-sequence-during-sinus-and-paced-rhythms-new-insights-from-use-of-high-resolution-doppler-and-ultrasonic-digital-particle-imaging-velocimetry
#20
Partho P Sengupta, Bijoy K Khandheria, Josef Korinek, Arshad Jahangir, Shiro Yoshifuku, Ilija Milosevic, Marek Belohlavek
OBJECTIVES: We sought to clarify the role of isovolumic intervals during a cardiac cycle by in vivo visualization of left ventricular (LV) intracavitary flow dynamics. BACKGROUND: Asynchronous LV deformation during isovolumic contraction (IVC) and isovolumic relaxation (IVR) might represent a transient feature of myocardial wall mechanics that reverses the direction of blood flow. METHODS: In 10 beating porcine hearts, the changes in LV intracavitary flow were recorded at baseline and after LV epicardial and right atrial pacing with high-resolution Doppler and contrast echocardiography...
February 27, 2007: Journal of the American College of Cardiology
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