The Björk-Shiley aortic prosthesis: flow characteristics, thrombus formation and tissue overgrowth.

Abstract Severe stenoses in arteries cause critical flow conditions which may be related to thrombus formation, artery compression and plaque cap rupture. The exact mechanism of these events and the conditions causing them are not well understood. Considerable work for flow in stenotic tubes have been reported in last twenty years and many interesting phenomena such as flow limitation, choking, flutter and wall collapse have been observed [3]. Stenosis severity, wall compliance and pressure conditions have been identified as dominating factors affecting wall deformation and flow and pressure fields. However, real arteries are rarely axisymmetric. Stenosis asymmetry may have considerable effects on wall stress and the critical flow characteristics.

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Computed tomography angiography as an adjunct to computational fluid dynamics for prediction of oxygenator thrombus formation

Perfusion ◽

10.1177/0267659120944105 ◽

2020 ◽

pp. 026765912094410

Author(s):

Robert G Conway ◽

Jiafeng Zhang ◽

Jean Jeudy ◽

Charles Evans ◽

Tieluo Li ◽

...

Keyword(s):

Fluid Dynamics ◽

Computed Tomography ◽

Computational Fluid Dynamics ◽

Computed Tomography Angiography ◽

Thrombus Formation ◽

Flow Analysis ◽

Flow Characteristics ◽

Region Of Interest ◽

Computational Fluid Dynamics Analysis ◽

Clot Burden

Introduction: Extracorporeal membrane oxygenation circuit performance can be compromised by oxygenator thrombosis. Stagnant blood flow in the oxygenator can increase the risk of thrombus formation. To minimize thrombogenic potential, computational fluid dynamics is frequently applied for identification of stagnant flow conditions. We investigate the use of computed tomography angiography to identify flow patterns associated with thrombus formation. Methods: A computed tomography angiography was performed on a Quadrox D oxygenator, and video densitometric parameters associated with flow stagnation were measured from the acquired videos. Computational fluid dynamics analysis of the same oxygenator was performed to establish computational fluid dynamics–based flow characteristics. Forty-one Quadrox D oxygenators were sectioned following completion of clinical use. Section images were analyzed with software to determine oxygenator clot burden. Linear regression was used to correlate clot burden to computed tomography angiography and computational fluid dynamics–based flow characteristics. Results: Clot burden from the explanted oxygenators demonstrated a well-defined pattern, with the largest clot burden at the corner opposite the blood inlet and outlet. The regression model predicted clot burden by region of interest as a function of time to first opacification on computed tomography angiography (R2 = 0.55). The explanted oxygenator clot burden map agreed well with the computed tomography angiography predicted clot burden map. The computational fluid dynamics parameter of residence time, when summed in the Z-direction, was partially predictive of clot burden (R2 = 0.35). Conclusion: In the studied oxygenator, clot burden follows a pattern consistent with clinical observations. Computed tomography angiography–based flow analysis provides a useful adjunct to computational fluid dynamics–based flow analysis in understanding oxygenator thrombus formation.

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Externally visible thrombus partially predicts internal thrombus deposition in extracorporeal membrane oxygenators

Perfusion ◽

10.1177/0267659116678679 ◽

2016 ◽

Vol 32 (4) ◽

pp. 301-305 ◽

Cited By ~ 3

Author(s):

Charles F. Evans ◽

Tieluo Li ◽

Vikas Mishra ◽

Diana L. Pratt ◽

Isa S.K. Mohammed ◽

...

Keyword(s):

Hollow Fiber ◽

Hollow Fiber Membrane ◽

Thrombus Formation ◽

Flow Characteristics ◽

Interquartile Range ◽

Fiber Membrane ◽

Patient Demographics ◽

Median Volume ◽

Membrane Oxygenators ◽

Imagej Software

Aim: We sought to quantify the location and volume of thrombus in used hollow-fiber membrane oxygenators and correlate the volume of thrombus with patient demographics, flow characteristics and anticoagulation parameters. Methods: Hollow-fiber membrane oxygenators (Quadrox D, Maquet, Rastatt, Germany) were collected after clinical use in ECMO circuits and divided into sections. Each section was digitally imaged and analyzed using ImageJ software. The location and total volume (cm3) of thrombus was calculated for different sections. In an effort to predict thrombus formation, we correlated thrombus volume with possible aggravating and mitigating variables. Results: We collected 41 oxygenators from 27 patients. Twenty-seven (66%) were configured in the veno-venous mode and 14 (34%) in the veno-arterial mode. The median duration of use was 131 hours (interquartile range 61–214 hours). Eighteen (44%) were removed when the patient recovered, six (15%) were removed after withdrawal of care and seventeen (41%) were exchanged. The median volume of thrombus was 11.4 cm3 (interquartile range 2.2–44.5 cm3). Conclusions: A multivariable linear regression model suggested that the combination of median flow, configuration of ECMO and visible thrombus partially predicted internal thrombus volume (adjusted R2=0.39).

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The Effect of Flow Characteristics on Thrombus Formation Rate and Deposition

ASME 2007 Summer Bioengineering Conference ◽

10.1115/sbc2007-176152 ◽

2007 ◽

Author(s):

S. Raz ◽

A. Enbal ◽

M. Rubinshi ◽

S. Einav

Keyword(s):

Blood Vessel ◽

Thrombus Formation ◽

Blood Clot ◽

Formation Rate ◽

Flow Characteristics ◽

Air Bubble ◽

Life Threatening

Embolism is defined as the obstruction of a blood vessel by a clump of material, such as a broken-off piece of plaque, a blood clot or air bubble, travels through the bloodstream and becomes lodged in a blood vessel. Depending on the size of the embolism and which blood vessel it is obstructing, the result can range from no symptoms whatsoever to a life-threatening emergency.

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The Björk – Shiley Aortic Prosthesis: Flow Characteristics of the Present Model vs. The Convexo-Concave Model

Scandinavian Journal of Thoracic and Cardiovascular Surgery ◽

10.3109/14017438009109849 ◽

1980 ◽

Vol 14 (1) ◽

pp. 1-5 ◽

Cited By ~ 18

Author(s):

Ajit P. Yoganathan ◽

Hollis H. Reamer ◽

William H. Corcoran ◽

Earl C. Harrison

Keyword(s):

Present Model ◽

Flow Characteristics ◽

Aortic Prosthesis

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Experimental Wall Shear Estimation as a Means of Predicting Thrombus Formation Within a 50cc Penn State Blood Pump

ASME 2010 Summer Bioengineering Conference, Parts A and B ◽

10.1115/sbc2010-19552 ◽

2010 ◽

Author(s):

Jason C. Nanna ◽

Stephen R. Topper ◽

Ning Yang ◽

Breigh N. Roszelle ◽

Steven Deutsch ◽

...

Keyword(s):

Heart Function ◽

Thrombus Formation ◽

Flow Characteristics ◽

Ventricular Assist Devices ◽

Ventricular Assist ◽

Shear Rates ◽

Penn State ◽

Wall Shear ◽

The 1960S ◽

Flow Stasis

The use of ventricular assist devices (VADs) as a means of cardiac support for patients with diminished heart function has been investigated since the 1960s [1]. While VAD therapy has had success in assisting the failing heart, thrombus formation within these devices is one of various complications that still limit its long term use. Research has shown that thrombus deposition in VADs is a function of the underlying fluid mechanics within these devices. Areas of flow stasis, high blood residence time, and wall shear rates under 500 s−1 are important flow characteristics driving thrombosis [2].

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The Starr-Edwards Aortic Ball Valve: Flow Characteristics, Thrombus Formation and Tissue Overgrowth

Biofluid Mechanics · 2 ◽

10.1007/978-1-4757-4610-5_14 ◽

1980 ◽

pp. 267-294 ◽

Cited By ~ 1

Author(s):

A. P. Yoganathan ◽

H. H. Reamer ◽

W. H. Corcoran ◽

E. C. Harrison ◽

I. A. Shulman ◽

...

Keyword(s):

Thrombus Formation ◽

Flow Characteristics ◽

Ball Valve

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Thrombus formation on artificial surfaces: Correlative microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016176x ◽

1990 ◽

Vol 48 (3) ◽

pp. 840-841

Author(s):

Quintin J. Lai ◽

Stuart L. Cooper ◽

Ralph M. Albrecht

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Low Voltage ◽

Thrombus Formation ◽

Blood Platelets ◽

Polymer Surfaces ◽

Flow Conditions ◽

Transmission Electron ◽

Adhesion Of Platelets ◽

Microscopic Techniques

Thrombus formation and embolization are significant problems for blood-contacting biomedical devices. Two major components of thrombi are blood platelets and the plasma protein, fibrinogen. Previous studies have examined interactions of platelets with polymer surfaces, fibrinogen with platelets, and platelets in suspension with spreading platelets attached to surfaces. Correlative microscopic techniques permit light microscopic observations of labeled living platelets, under static or flow conditions, followed by the observation of identical platelets by electron microscopy. Videoenhanced, differential interference contrast (DIC) light microscopy permits high-resolution, real-time imaging of live platelets and their interactions with surfaces. Interference reflection microscopy (IRM) provides information on the focal adhesion of platelets on surfaces. High voltage, transmission electron microscopy (HVEM) allows observation of platelet cytoskeletal structure of whole mount preparations. Low-voltage, high resolution, scanning electron microscopy allows observation of fine surface detail of platelets. Colloidal gold-labeled fibrinogen, used to identify the Gp Ilb/IIIa membrane receptor for fibrinogen, can be detected in all the above microscopies.

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