The Haemodynamics of Asymmetric Stenoses

Dodds, Simon

doi:10.1053/ejvs.2002.1729

Cited by 32 publications

(27 citation statements)

References 8 publications

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“…There are good reasons to express stenotic value of ICAS as distal CSA rather than distal diameter reduction percentage. First of all, reduction of CSA better represents the hemodynamic impact of—especially an eccentric—stenosis [24]. In addition, measurement of CSA is also independent of the projection, that is, in case of DSA and diameter measurement on the direction of X-rays (Fig 2).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Freehand B-Mode and Power-Mode 3D Ultrasound for Visualisation and Grading of Internal Carotid Artery Stenosis

2017

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BackgroundCurrently, colour-coded duplex sonography (2D-CDS) is clinical standard for detection and grading of internal carotid artery stenosis (ICAS). However, unlike angiographic imaging modalities, 2D-CDS assesses ICAS by its hemodynamic effects rather than luminal changes. Aim of this study was to evaluate freehand 3D ultrasound (3DUS) for direct visualisation and quantification of ICAS.MethodsThirty-seven patients with 43 ICAS were examined with 2D-CDS as reference standard and with freehand B-mode respectively power-mode 3DUS. Stenotic value of 3D reconstructed ICAS was calculated as distal diameter respectively distal cross-sectional area (CSA) reduction percentage and compared with 2D-CDS.ResultsThere was a trend but no significant difference in successful 3D reconstruction of ICAS between B-mode and power mode (examiner 1 {Ex1} 81% versus 93%, examiner 2 {Ex2} 84% versus 88%). Inter-rater agreement was best for power-mode 3DUS and assessment of stenotic value as distal CSA reduction percentage (intraclass correlation coefficient {ICC} 0.90) followed by power-mode 3DUS and distal diameter reduction percentage (ICC 0.81). Inter-rater agreement was poor for B-mode 3DUS (ICC, distal CSA reduction 0.36, distal diameter reduction 0.51). Intra-rater agreement for power-mode 3DUS was good for both measuring methods (ICC, distal CSA reduction 0.88 {Ex1} and 0.78 {Ex2}; ICC, distal diameter reduction 0.83 {Ex1} and 0.76 {Ex2}). In comparison to 2D-CDS inter-method agreement was good and clearly better for power-mode 3DUS (ICC, distal diameter reduction percentage: Ex1 0.85, Ex2 0.78; distal CSA reduction percentage: Ex1 0.63, Ex2 0.57) than for B-mode 3DUS (ICC, distal diameter reduction percentage: Ex1 0.40, Ex2 0.52; distal CSA reduction percentage: Ex1 0.15, Ex2 0.51).ConclusionsNon-invasive power-mode 3DUS is superior to B-mode 3DUS for imaging and quantification of ICAS. Thereby, further studies are warranted which should now compare power-mode 3DUS with the angiographic gold standard imaging modalities for quantification of ICAS, i.e. with CTA or CE-MRA.

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Section: Discussionmentioning

confidence: 99%

Evaluation of Freehand B-Mode and Power-Mode 3D Ultrasound for Visualisation and Grading of Internal Carotid Artery Stenosis

2017

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“…Post-stenotic deceleration of blood flow induces flow separation and recirculation zones (vortices). Such regions of flow separation and statis are favored sites for the development of thrombosis and atherosclerosis [8]. A closer inspection on these patterns reveals that complex recirculation zones develop in the vicinity of the sections D3, D5 and D7 of the RCA during systolic phase of both types of the input waveforms (Fig.…”

Section: Pressure 42mentioning

confidence: 92%

“…It is widely believed that atherosclerosis development and progression are affected by many risk factors, such as static pressure, wall shear stress (WSS), blood viscosity, flow velocity, etc. Vascular geometry is another factor influencing strongly the flow patterns and generating a pre-existing atherogenic hemodynamic environment [6][7][8][9].…”

mentioning

confidence: 99%

Effects of different types of input waveforms in patient-specific right coronary atherosclerosis hemodynamics analysis

Bernad¹,

Bernad²,

Barbat³

et al. 2010

Int. J. DNE

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Accurate fluid mechanics models are important tools for predicting the flow field in the coronary artery for understanding the relationship between hemodynamics and the initiation and progression of atherosclerosis. The purpose of this paper is to asses non-invasively hemodynamic parameters such as disturbed flows, pressure distribution and wall shear stress with computational fluid dynamics (CFD) in human right coronary artery (RCA) using patient-specific data from in vivo computed tomographic (CT) angiography, using two different pulsatile input waveforms. In order to produce a realistic three-dimensional model of the RCA anatomy, CT-datasets were acquired by a four-row-detector CT-scanner. Digital files in Digital Imaging and Communications in Medicine (DICOM) file format, containing cross-sectional information were then imported to CFD software package for reconstruction. The numerical analysis examines closely the effect of a different input waveforms model on the hemodynamic characteristics such as secondary flow, flow separation and wall shear stress in the multiple stenosed RCA.

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“…An alternative means for invasive flow measurements is presented by the calculation of models in which blood flow can be virtually simulated, a method that is called computational fluid dynamics (CFD). In fact, several in vitro studies [6,10,16,17,18] have shown that CFD allows reliable physiologic blood flow simulation and measurements of WSS, wall pressure, and mass flow. A detailed hemodynamic evaluation of disturbed flow in the post stenotic region may give additional insight of the progression of atherosclerosis and may have useful clinical value, such as early detection of a highly stenosed artery segment, prediction of future disease progression, and treatment planning 2.1 Artery reconstruction A Somatom Sensation 64 Scanner (Siemens Medical Systems, Erlangen, Germany) was used in non-enhanced spiral scan technique with a slice thickness of 0.75 mm, a table feed of 1 mm/s, and an increment of 2 mm (Fig.…”

Section: Methodsmentioning

confidence: 99%

Clinical important hemodynamic characteristics for serial stenosed coronary artery

Bernad¹,

Bernad²,

Totorean³

et al. 2015

Int. J. DNE

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Effects of serial stenosis on coronary hemodynamics are investigated in the human right coronary artery (RCA) by blood flow analysis. The 3D reconstruction of the geometry of the stenosed coronary artery uses the multislice computerized tomography serial images method. Results of the numerical analysis present the hemodynamic characteristics of the serial stenosed coronary artery throughout the flow separation, pressure drop and wall shear stress. The pressure loss associated with recirculation region created in the vicinity of each constriction was found to be large. In two stenoses the corresponding pressure gradients are around 30 mmHg and correspond to the stenosis with fractional flow reserve-FFR < 0.7 (value associated to the severe stenosis). Distal to the stenosis, flow is associated with fluctuations in the wall shear stress and vorticity. Both FFR and CFD analysis help identify intermediate lesions that require intervention and reduce unnecessary procedures with potential complications.

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The Haemodynamics of Asymmetric Stenoses

Cited by 32 publications

References 8 publications

Evaluation of Freehand B-Mode and Power-Mode 3D Ultrasound for Visualisation and Grading of Internal Carotid Artery Stenosis

Evaluation of Freehand B-Mode and Power-Mode 3D Ultrasound for Visualisation and Grading of Internal Carotid Artery Stenosis

Effects of different types of input waveforms in patient-specific right coronary atherosclerosis hemodynamics analysis

Clinical important hemodynamic characteristics for serial stenosed coronary artery

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