What does this research mean for the field?

The geometry of the carotid bulb, rather than flow characteristics, is the primary determinant of the hemodynamic environment and subsequent risk of restenosis following carotid endarterectomy closure procedures. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

May 1, 2025International Journal for Numerical Methods in Biomedical EngineeringOpen Access

Modeling Hemodynamic Effects of the Closure Procedure of Carotid Artery Endarterectomy

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Why the study?

It is unclear why some patients develop restenosis after carotid endarterectomy and whether the closure procedure is linked to greater rates of restenosis.

Does patch closure compared to primary closure alter hemodynamic parameters in patients post-carotid endarterectomy?

Structured PICO

Does patch closure compared to primary closure alter hemodynamic parameters in patients post-carotid endarterectomy?

Population

2 patients post-carotid endarterectomy (CEA), one with patch closure who restenosed at 8 years, and one with primary closure who did not restenose.

Intervention

Patch closure

Comparator

Primary closure

Outcome

Hemodynamic parameters (wall shear stress, oscillatory shear index, vorticity, kinetic energy, vortex coreline length) derived from computational fluid dynamicssurrogate

Differences in carotid endarterectomy outcomes may be linked to the geometry rendered by the closing method, with patch closure potentially creating nonphysiological hemodynamics that promote restenosis.

Limitations

Small sample size restricts generalizability
Material properties, including distensibility, of the vessel wall were unavailable
Patient-specific flow rate waveforms were only available in the CCA and ICA, requiring estimation for the ECA
Use of a Newtonian viscosity model and Womersley flow profile
Certain patient- and intervention-specific factors were not considered (e.g., suture technique, patch material)

Implication

Patch closure may produce unfavorable carotid hemodynamics; leaves open optimal technique to reduce restenosis.

Abstract

Currently, it is unclear why some patients experience restenosis after carotid endarterectomy (CEA) and whether the closing procedure is linked to greater rates of restenosis. Here, the morphology and hemodynamics are compared for the carotid bulb of two patients post-CEA. One carotid bulb was closed with a patch which later suffered a restenosis, while the other patient's bulb was treated using primary closure and did not. Contrast-enhanced magnetic resonance angiography (CE-MRA) was segmented to provide the domain for computational fluid dynamics (CFD). Flowrate waveforms measured with phase-contrast MR were provided for the common carotid artery (CCA) and internal carotid artery (ICA), while only the mean flow rate was provided for the external carotid artery (ECA), requiring the ECA waveform to be calculated. A Womersley profile was applied to the CCA inlet and ECA outlet, with a traction-free boundary condition applied to the ICA outlet. The patch patient who restenosed exhibited a nonphysiological hemodynamic environment that differed from the flow environment observed in the healthy, contralateral bulb. In contrast, the hemodynamics of the primary closure patient who underwent a successful CEA showed more favorable levels and trends of WSS as well as healthy mixing from vortices that were both present in the healthy, contralateral bulb. Changing model parameters such as flow rate, wall compliance, and flow waveforms did not alter these conclusions. Therefore, the geometry of the carotid bulb, as opposed to flow characteristics, seems responsible for the observed differences between these two cases in hemodynamic environments and subsequent outcomes.