Complex vascular anatomy could increase the risk of periprocedural stroke during carotid artery stenting (CAS). However, no randomize study has provided evidence showing this potential difficulty should inform the choice between carotid stenting and endarterectomy. 

This study included 184 patients with symptomatic lesions of the internal carotid randomized to CAS vs. endarterectomy in the context of the ICSS trial (International Carotid Stenting Study). Patients had all received an MRI (n=126) or a CT (n=58) prior to procedure, and an MRI after procedure.

The study looked at the association between aortic arch configuration, angles of supra aortic vessels, stenosis degree and length, and the presence of plaque ulceration, with the presence of at least one or more new ipsilateral ischemic lesions on diffusion-weighted magnetic resonance imaging (DWI+) after procedure.

49 of the 97 patients in the CAS group (51%) and 14 of the 87 in the endarterectomy group (16%) presented new lesions on DWI (OR 6.0; CI 95%, 2.9–12.4; p<0.001).

In the CAS group, type 2/3 aortic arch configuration (OR 2.8; CI 95%, 1.1–7.1; p=0.027) and internal carotid angulation (≥60° vs <60°; OR, 4.1; CI 95% 1.7–10.1; p=0.002) were associated to DWI+, even after correction for different factors, such as age.

The latter wasn’t true for the endarterectomy group, given it was not possible to identify independent predictors of new lesions on DWI.

The greatest risk for CAS over endarterectomy was seen in patients with the largest internal carotid angle (≥60°) (OR 11.8; IC 95% 4.1–34.1).

Conclusion

The complex anatomy of the aortic arch and mainly the tortuosity of the internal carotid increase the risk of ischemic events during CAS in symptomatic patients, which did not result true for endarterectomy. Vascular anatomy should be taken into account when choosing either one.

Editorial Comment

The complexity of the aortic arch and supra aortic vessels will certainly increase the technical challenge of CAS. The repeated attempts to advance catheters or inductor sheaths could lead to endothelium traumas or even plaque destruction, which in turn could lead to cerebral embolism.

The ICSS protocol did not consider any details as regards measures to prevent this kind of inconveniencies, such as the number of attempts before giving up, limiting the number of maneuvers, heparin concentration, or necessary experience for the most challenging cases.

Researchers might have neglected the necessary precautions that should be taken into account when interpreting outcomes.

Plaque characteristics, stenosis degree, plaque extension or the presence of ulceration previously assessed with MRI or CT were not predictors of new lesions at diffusion-weighted magnetic resonance after CAS.

Original Title: Vascular Anatomy Predicts the Risk of Cerebral Ischemia in Patients Randomized to Carotid Stenting Versus Endarterectomy.

Reference: Mandy D. Müller et al. Stroke. 2017 May; 48(5):1285-1292.

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