Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics – a pilot study

Demirel, Serdar; Chen, Dongwei; Mei, Yuqian; Partovi, Sasan; Tengg-Kobligk, Hendrik von; Dadrich, Monika; Böckler, Dittmar; Kauczor, HU; Müller–Eschner, Matthias

doi:10.1177/1708538114552836

Cited by 10 publications

(3 citation statements)

References 63 publications

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“…Our group recently used computational fluid dynamics to compare postoperative morphologic and rheologic conditions after e-CEA vs s-CEA. 4 Interestingly, the systolic peak of the e-CEA model showed a gradually decreased pressure along the stream path, whereas the s-CEA model revealed a relatively high pressure (about 180 Pa) at the carotid bulb. This contradicts the theory of Marrocco-Trischitta et al 2 that s-CEA has a disadvantage regarding elastic properties of the carotid sinus vascular wall.…”

Section: Replymentioning

confidence: 93%

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Demirel

2015

Journal of Vascular Surgery

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from carotid baroreceptors and chemoreceptors ascend in anatomic proximity in the carotid sinus nerve, and therefore, the sequelae of baroreceptor and chemoreceptor denervation as a result of an iatrogenic injury typically arise in parallel.If the theory of Demirel et al were correct, patients who undergo bilateral e-CEA would represent a human model of carotid sinus denervation. In fact, we proved in our previous study 2 that this is not the case. Also, in patients treated with bilateral CEA not only were both baroreflexes and chemoreflexes preserved regardless the surgical technique, but unexpectedly, baroreflexes appeared better maintained in e-CEA than in patch CEA. Finally, we found that e-CEA, even when performed on both sides, did not increase long-term arterial pressure variability, and this suggests that perioperative hemodynamic derangements can be attributed to the temporary effects of surgical trauma.Finally, the remarks about our methods by Demirel et al 1 appear incorrect and inaccurate. In humans, the lack of carotid baroreceptors is not completely compensated by aortic and cardiopulmonary baroreceptors. 4 Furthermore, we did not perform only standard cardiovascular reflex tests but also spectral analysis of heart rate and blood pressure variability and concurrent peripheral chemoreflex function analysis that specifically accounts for the integrity of the carotid sinus nerve. Rather, the authors claim that in their study "unilateral carotid baroreflex function could be assessed in an invasive way, allowing a full pressure transmission to the carotid baroreceptors located in the carotid bulb." In fact, they more prosaically retrospectively reviewed patient records and compared perioperative routine records of two nonrandomized nor case-matched groups of patients.In conclusion, it should be apparent that the "carotid sinus denervation by e-CEA" theory is dead.

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Section: Replymentioning

confidence: 93%

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Demirel

2015

Journal of Vascular Surgery

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“…Fig. 2), and zero pressure was set at the extended outlets [23]. No slip and rigid boundary conditions were imposed at the walls.…”

Section: Methodsmentioning

confidence: 99%

Tortuosity and Proximal-Specific Hemodynamics Associated with Plaque Location in the Carotid Bulb Stenosis

Ren

Zhao

et al. 2023

J Vasc Res

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Background: Atherosclerotic plaque locations in the carotid bulb increasingly have been found to be associated with patterns of ischemic lesions and plaque progression. However, the occurrence of carotid bulb plaque is a complex process. We aimed to investigate plaque characteristics and geometric and hemodynamic parameters among patients with body and apical plaques of the carotid bulb and to identify the mechanism of bulb plaque formation and location. Methods: Consecutive patients with single carotid bulb stenosis (50–99%) were enrolled retrospectively. Patients were divided into body and apical plaque groups based on plaque location. Plaque location and characteristics were identified and measured on high-resolution vessel wall magnetic resonance imaging. Geometric parameters were derived from time-of-flight magnetic resonance imaging. Computational fluid dynamics simulations were performed to quantify wall shear stress (WSS) and four associated WSS-based metrics on the plaque side, on the non-plaque side, and in different parts of the lesion. Plaque characteristics and geometric and hemodynamic parameters were compared, and their associations with the plaque location were determined. Results: Seventy patients were recruited (41 body plaques and 29 apical plaques). WSSplaque values were lower than WSSnon-plaque values for all plaques (median [interquartile range], 12.59 [9.83–22.14] vs. 17.27 [11.63–27.63] Pa, p = 0.001). In a multivariate binary logistic regression, the tortuosity of the stenosed region, the magnitudes of the mean relative residence time, and the minimum transverse WSS in the proximal part of the lesion were the key factors independently associated with plaque location (p = 0.022, 0.013, and 0.012, respectively). Conclusions: Plaque formation was associated with the local flow pattern, and the tortuosity and proximal-specific hemodynamics were significantly associated with plaque location in the carotid bulb.

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“…Scan and reconstruction parameters were as follows: 120 kV, 120 mAs, reconstructed slice thickness 0.75 mm, reconstruction increment 0.7mm, pixel spacing 0.4x0.4mm and 90 ml contrast medium (iomeprol with 400 mg iodine per ml, Imeron 400, Bracco Diagnostics, Princeton, NJ, USA) with 50 ml saline chaser. The MDCT datasets of the right carotid arteries of PI and PIII have been used in our previous study [13]. In the current study, these two datasets were newly segmented and simulations were performed based on the newly reconstructed models.…”

Section: Methodsmentioning

confidence: 99%

Hemodynamics analyses in treated and untreated carotid arteries of the same patient: A preliminary study based on three patient cases

Mei

Müller–Eschner

et al. 2015

BME

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Abstract. Carotid atherosclerotic disease is highly related to cerebrovascular events. Carotid endarterectomy is the common operation method to treat this disease. In this study, hemodynamics analyses are performed on the carotid arteries in three patients, whose right carotid artery had been treated by carotid endarterectomy and the left carotid artery remained untreated. Flow and loading conditions are compared between these treated and untreated carotid arteries and evaluation of the operative results is discussed. Patient-specific models are reconstructed from MDCT data. Intraoperative ultrasound flow measurements are performed on the treated carotid arteries and the obtained data are used as the boundary conditions of the models and the validations of the computational results. Finite volume method is employed to solve the transport equations and the flow and loading conditions of the models are reported. The results indicate that: (i) in two of the three patients, the internal-to-external flow rate ratio in the untreated carotid artery is larger than that in the treated one, and the average overall flow split ratio by summing up the data of both the left and right carotid arteries is about 2.15; (ii) in the carotid bulb, high wall shear stress occurs at the bifurcation near the external carotid artery in all of the cases without hard plaques; (iii) the operated arteries present low time-averaged wall shear stress at the carotid bulb, especially for the treated arteries with patch technique, indicating the possibility of the recurrence of stenosis; (iv) high temporal gradient of wall shear stress (>35 Pa/s) is shown in the narrowing regions along the vessels; and (v) in the carotid arteries without serious stenosis, the maximum velocity magnitude during mid-diastole is 32~37% of that at systolic peak, however, in the carotid artery with 50% stenosis by hard plaques, this value is nearly doubled (64%). The computational work quantifies flow and loading distributions in the S299treated and untreated carotid arteries of the same patient, contributing to evaluation of the operative results and indicating the recurrent sites of potential atheromatous plaques.

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Comparison of morphological and rheological conditions between conventional and eversion carotid endarterectomy using computational fluid dynamics – a pilot study

Cited by 10 publications

References 63 publications

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Tortuosity and Proximal-Specific Hemodynamics Associated with Plaque Location in the Carotid Bulb Stenosis

Hemodynamics analyses in treated and untreated carotid arteries of the same patient: A preliminary study based on three patient cases

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