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Pulsatile flow

About: Pulsatile flow is a research topic. Over the lifetime, 6278 publications have been published within this topic receiving 149638 citations.


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Journal ArticleDOI
14 Feb 2013-PLOS ONE
TL;DR: A physiological flow model based on short-term temporal changes in blood flow observed in vivo and compared it to static culture and steady flow at a fixed pulse frequency shows significant changes in gene regulation as a function of temporally variable flow, indicating a reduced wound phenotype more representative of quiescence.
Abstract: Endothelial cell (EC) function is mediated by variable hemodynamic shear stress patterns at the vascular wall, where complex shear stress profiles directly correlate with blood flow conditions that vary temporally based on metabolic demand The interactions of these more complex and variable shear fields with EC have not been represented in hemodynamic flow models We hypothesized that EC exposed to pulsatile shear stress that changes in magnitude and duration, modeled directly from real-time physiological variations in heart rate, would elicit phenotypic changes as relevant to their critical roles in thrombosis, hemostasis, and inflammation Here we designed a physiological flow (PF) model based on short-term temporal changes in blood flow observed in vivo and compared it to static culture and steady flow (SF) at a fixed pulse frequency of 13 Hz Results show significant changes in gene regulation as a function of temporally variable flow, indicating a reduced wound phenotype more representative of quiescence EC cultured under PF exhibited significantly higher endothelial nitric oxide synthase (eNOS) activity (PF: 1760±119 nmol/105 EC; SF: 1150±125 nmol/105 EC, p = 0002) and lower TNF-a-induced HL-60 leukocyte adhesion (PF: 37±6 HL-60 cells/mm2; SF: 111±18 HL-60/mm2, p = 0003) than cells cultured under SF which is consistent with a more quiescent anti-inflammatory and anti-thrombotic phenotype In vitro models have become increasingly adept at mimicking natural physiology and in doing so have clarified the importance of both chemical and physical cues that drive cell function These data illustrate that the variability in metabolic demand and subsequent changes in perfusion resulting in constantly variable shear stress plays a key role in EC function that has not previously been described

60 citations

Journal ArticleDOI
TL;DR: A prototype for a clinically applicable pulsatile jet infusion system for accelerating thrombolysis was designed and the effect of initial perturbation of the thrombus by a guide wire appears to be less important than theThrombus disruption and accelerated thrombosis caused by the pulsatile delivery system.
Abstract: Forceful local pulsatile infusion of fibrinolytic enzyme disrupts thrombi, increases clot surface area, and thereby hastens enzyme action compared with conventional constant infusion methods, which are time consuming and therefore expensive. Prolonged thrombolytic therapy is associated with increased patient morbidity. A prototype for a clinically applicable pulsatile jet infusion system for accelerating thrombolysis was designed. The system is adaptable to standard angiographic catheters and techniques. The core of the system is a reciprocating syringe pump that delivers small volumes of thrombolytic enzyme in short, rapid, frequent pulses at high exit-jet velocity through any side-hole catheter (the smallest used was a 3-F catheter). Comparison of this system with a constant infusion system was made in vivo in a 48-hour-old thrombus model in rabbit inferior vena cava (IVC). One hour of lysis by streptokinase was conducted with each of the methods. In the first experiment, the IVC thrombi were left intac...

60 citations

Journal ArticleDOI
TL;DR: The combined MRI/CFD is expected to provide more reliable information about the full three-dimensional velocity field and to further explore the potential for in vivo applications.
Abstract: A combined magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) modeling study was carried out for pulsatile flow in a carotid bifurcation phantom. The aim of the study was to quantify differences in flow patterns between MRI measurement and MRI-based CFD simulations and to further explore the potential for in vivo applications. The computational model was reconstructed from high resolution magnetic resonance (MR) scans. Velocities derived from phase-contrast MR measurements were used as boundary conditions for the CFD calculation. Detailed comparisons of velocity patterns were made between the CFD results and MRI measurements. Good agreement was achieved for the main velocity component in both well-behaved flow (in the common carotid) and disturbed region (in the carotid sinus). Comparison of in-plane velocity vectors showed less satisfactory consistency and revealed that the MR measurements obtained were inadequate to depict the secondary flow pattern as expected. It can be concluded that the combined MRI/CFD is expected to provide more reliable information about the full three-dimensional velocity field. © 2003 Biomedical Engineering Society. PAC2003: 8761Lh, 8719Uv, 8385Pt, 8710+e

60 citations

Journal ArticleDOI
TL;DR: Investigation of the capacity of the distal stomach to generate transpyloric flow pulses in the absence of the proximal stomach found that the stroke volume of individual pulses is greater, and the mechanisms responsible for emptying are modified.

60 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023274
2022641
2021170
2020181
2019171
2018189