Stent impact on the geometry of the carotid bifurcation and the course of the internal carotid artery

Abstract

A measurement system is proposed to evaluate reconstructive effects of carotid stents on the geometry of the carotid bifurcation and the course of the internal carotid artery. To describe deviations of the stenotic internal carotid artery (ICA) from the extended axis of the common carotid artery (CCA) the CCA-ICA angle is measured between the CCA midaxis and the midaxis of the stenotic ICA segment. Maximal extensions of ICA tortuosities perpendicular to the course of the CCA axis are defined as ICA offset. The measurements were applied to DSA images of 224 carotid stenoses to evaluate variation and correlation between the two parameters. Comparative pre- and post-stent evaluation was performed in two series of 55 and 31 carotid stenoses treated with Wallstents and in a historic control group of 35 stenoses treated with Strecker stents. Straight course of the ICA was associated with low angle and low offset values, whereas tortuous course of the ICA showed larger angle and offset. A moderate linear correlation between the two parameters was found. Corresponding to a straightening of the stented segment, Wallstents reduced mean angle and offset values significantly. In five cases of the second series of Wallstents, transferrals of curves above the distal stent end associated with kinks were observed, and offset remained constant or increased. Strecker stent implantation caused no significant changes of bifurcational geometry. The proposed parameters corresponded to visual aspects of ICA tortuosity and detected reconstructive effects of self-expanding Wallstents on the ICA course. The measurement system may provide a basis for geometric evaluation of different stent types or implantation concepts with the aim: to optimize anatomic recanalization results in tortuous high angle-high offset bifurcations.

Delivery and release of nitinol stent in carotid artery and their interactions: A finite element analysis

“…4a1 and b1), which was observed in clinical results (Berkefeld et al, 2002) and in vitro experiments (Tanaka et al, 2004). Although the long-term clinical impacts of these changes are not clear now (Vos et al, 2005), the results indicate that the different stent designs can cause different vessel tortuosity changes.…”

“…The model is composed of a carotid tissue (vessel and plaque), nitinol stent and sheath. The tissue was built based on the previous studies (Berkefeld et al, 2002), and the vessel consists of the common, internal and external carotid artery (CCA, ICA and ECA). The measure of ICA tortuosity is shown in Fig.…”

Open-cell versus closed-cell stent design differences in blood flow velocities after carotid stenting

“…6,8,27,28 In fact, a 2/3 reduction in compliance of the carotid artery after CAS has been demonstrated 6. This alteration in compliance may be a contributing factor to the elevated velocities seen after CAS.…”

Impact of head movements on morphology and flow in the internal carotid artery after carotid angioplasty and stenting versus endarterectomy

“…Berkefeld et al 13 proposed a method of measuring the common carotid artery-ICA angle and the ICA offset before and after carotid stenting. They found a significant reduction in both common carotid artery-ICA angulation and ICA offset after CAS, compared with baseline, in their patients.…”

“…[11][12][13] The carotid bifurcation is located in a highly mobile part of the human anatomy, and after the introduction of a stent, it is only partially able to accommodate the changes in geometry that result from physiologic movements of the head, which may lead to kinking at the distal end of the stent. 14 Although the clinical importance of carotid artery kinking remains controversial, significant flow changes during head movements have been found to be associated with ICA kinking.…”