Carotid Artery Dynamics during Head Movements: A Reason for Concern with Regard to Carotid Stenting?

A, Vos; Linsen, Matteus A. M.; Marcus, J. Tim; Berg, Jos C. van den; Vos, Jan Albert; Rauwerda, Jan A.; Wisselink, Willem

doi:10.1177/152660280301000503

Cited by 30 publications

(30 citation statements)

References 32 publications

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“…This decision was motivated by an interest in investigating repeated loading events of the lesion such as pre-stenting expansion by a balloon, stenting followed by poststenting balloon expansion; as well as the effects of physiological loading of the lesion post-stenting due to movement. 38,45 The stress-strain response on unloading could have been used for the fit of f ¥ and i instead which would be of greater benefit to FE models in which only one loading-unloading cycle was present. Regardless the proposed model is more appropriate than the assumption of elasticity in determining the unloading behavior of the plaque, particularly as stress softening phenomena observed during the first unloading cycle were more significant than hysteresis effects in subsequent loading and unloading cycles.…”

Section: Discussionmentioning

confidence: 99%

“…In the case of stenting procedures where pre-or post-expansion is used the loading mechanism on the tissue will be similar in each loading phase allowing models of inelasticity similar to that proposed here to be used. For models that include different loading regimes such as bending or torsion that occur in peripheral arteries 45 an anisotropic inelastic model would need to be implemented. 13 The loading behavior defined by Eq.…”

Section: Discussionmentioning

confidence: 99%

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Inelasticity of Human Carotid Atherosclerotic Plaque

et al. 2011

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Little mechanical test data exists regarding the inelastic behavior of atherosclerotic plaques. As a result finite element (FE) models of stenting procedures commonly use hyperelastic material models to describe the soft tissue response thus limiting the accuracy of the model to the expansion stage of stent implantation and leave them unable to predict the lumen gain. In this study, cyclic mechanical tests were performed to characterize the inelastic behavior of fresh human carotid atherosclerotic plaque tissue due to radial compressive loading. Plaques were classified clinically as either mixed (M), calcified (Ca), or echolucent (E). An approximately linear increase in the plastic deformation was observed with increases in the peak applied strain for all plaque types. While calcified plaques generally appeared stiffest, it was observed that the clinical classification of plaques had no significant effect on the magnitude of permanent deformation on unloading. The test data was characterized using a constitutive model that accounts for both permanent deformation and stress softening to describe the compressive plaque behavior on unloading. Material constants are reported for individual plaques as well as mean values for each plaque classification. This data can be considered as a first step in characterizing the inelastic behavior of atherosclerotic plaques and could be used in combination with future mechanical data to improve the predictive capabilities of FE models of angioplasty and stenting procedures particularly in relation to lumen gain.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Inelasticity of Human Carotid Atherosclerotic Plaque

et al. 2011

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“…Also, since the disease itself may influence the magnitude and pattern of posture-related geometric alterations, future data should also include geometric changes due to head rotation in the setting of advanced disease. Stent implantation in carotid arteries is not common, but it is performed in about 20-30% of patients when endarterectomy is not possible such as in patients with highly calcified lesions or in carotids with complicated geometries [24]. Previous studies such as those by Valibhoy et al [25] and Diehm et al [26] have reported that carotid stents fracture in some occasions.…”

Section: Discussionmentioning

confidence: 99%

“…A parallel imaging technique (SENSE factor 2) was employed to reduce acquisition time. Variable flip angle (16)(17)(18)(19)(20)(21)(22)(23)(24) • ) and gradient first moment nulling techniques were applied to decrease saturation effects of inflowing blood and reduce signal loss due to complex flow, respectively. Each subject was imaged in two different scanning sessions on the same day corresponding to the two head postures examined: 1) a neutral head posture with the subject in the supine position; and 2) a rightward head rotation posture with the subject in the prone position.…”

Section: B Mrimentioning

confidence: 99%

Effect of Posture Change on the Geometric Features of the Healthy Carotid Bifurcation

Aristokleous

Seimenis²,

Papaharilaou

et al. 2011

IEEE Trans. Inform. Technol. Biomed.

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Abstract-Segmented cross-sectional MRI images were used to construct 3-D virtual models of the carotid bifurcation in ten healthy volunteers. Geometric features, such as bifurcation angle, internal carotid artery (ICA) angle, planarity angle, asymmetry angle, tortuosity, curvature, bifurcation area ratio, ICA/common carotid artery (CCA), external carotid artery (ECA)/CCA, and ECA/ICA diameter ratios, were calculated for both carotids in two head postures: 1) the supine neutral position; and 2) the prone sleeping position with head rotation to the right (∼80• ). The results obtained have shown that head rotation causes 1) significant variations in bifurcation angle [32% mean increase for the right carotid (RC) and 21% mean decrease for the left carotid (LC)] and internal carotid artery angle (97% mean increase for the RC, 43% mean decrease for the LC); 2) a slight increase in planarity and asymmetry angles for both RC and LC; 3) minor and variable curvature changes for the CCA and for the branches; 4) slight tortuosity changes for the braches but not for the CCA; and 5) unsubstantial alterations in area and diameter ratios (percentage changes <10%). The significant geometric changes observed in most subjects with head posture may also cause significant changes in bifurcation hemodynamics and warrant future investigation of the hemodynamic parameters related to the development of atherosclerotic disease such as low oscillating wall shear stress and particle residence times.

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“…The proposed hypothetical mechanism for this phenomenon is that head rotation ispilateral to the stenotic ICA applies significant axial, radial, and torsion shear forces on the affected critically stenotic ICA. 8,9 It has become almost conventional to consider a diagnosis of positional vertebrobasilar ischemia in patients presenting with symptoms specifically associated with lateral neck rotation or extension. 10,11 However, the positional carotid artery occlusion appears to be rare, and the pathological mechanism is not clear.…”

Section: Discussionmentioning

confidence: 99%