Both carotid tortuosity and complex configuration of the aortic arch were associated with an increase in cerebral ischemia with CAS, but not with CEA.
Symptomatic carotid stenosis may be better treated with stenting than endarterectomy when the vascular anatomy is complex, according to new data from the International Carotid Stenting Study (ICSS).
While this is only one of many factors that must be considered when selecting a treatment option, the study is helpful in that it identifies specific parameters for defining complex carotid anatomy, Perry Ng, MD (Centura Health Physician Group, Denver, CO), told Neurovascular Exchange.
In an email, Ng described the relative pros and cons of carotid artery stenting (CAS) versus endarterectomy (CEA) for management of symptomatic carotid stenosis. While there is less experience with stenting and a higher risk of periprocedural stroke, he pointed out, CEA has been linked with a greater risk of periprocedural cardiac events. In addition, older patients have been shown to have poorer outcomes with CAS, which could be a reflection of greater vascular tortuosity and unfolding.
“The current study is important as it objectively compares the effect of vascular tortuosity on periprocedural stroke with CAS and CEA and by doing so can aid in the deciding the treatment of choice in individual patients,” he noted.
For the ICSS substudy, senior author Leo H. Bonati, MD (University Hospital Basel, Switzerland), and colleagues looked at 184 patients with symptomatic carotid artery stenosis who had been randomized to undergo CAS (n = 97) or CEA (n = 87). Of these, 126 underwent MRI imaging and 58 underwent CT angiography at baseline as well as MRI before and after treatment.
Overall, 49 of the patients who underwent stenting (51%) had evidence of at least one new ischemic brain lesion on diffusion-weighted MRI (DW-MRI) after treatment. After endarterectomy, only 14 patients (16%) had new DWI lesions, for an odds ratio of 6.0 (95% CI 2.9-12.4, P < 0.001).
Among CAS patients, the presence of an aortic arch configuration Type 2 or 3 and a large internal carotid artery angle were both associated with the presence of new DWI lesions, even after correcting for age. In addition, risk of new lesions was greater when an expert score of anatomic difficulty for the procedure was higher. Among CEA patients, however, there was no link between carotid anatomy and new DWI lesions.
Likelihood of Posttreatment DWI Brain Lesions
|
|
OR (95% CI) |
P Value |
|
Aortic Arch Configuration type 2 or 3 CAS CEA |
2.83 (1.13-7.11) 3.46 (0.70-17.10) |
0.027 NS |
|
Largest Internal Carotid Angle ≥ 60° CAS CEA |
4.10 (1.67-10.06) 0.89 (0.28-2.81) |
0.002 NS |
|
Expert Score for Anatomic Suitability ≥ 4.3 CAS CEA |
3.15 (1.26-7.87) 1.60 (0.44-5.87) |
0.014 NS |
Risk of developing DWI lesions was increased even more among patients who underwent stenting compared endarterectomy when the largest internal carotid artery angle was ≥ 60° (OR 11.8; 95% CI, 4.1-34.1) than if it was < 60° (OR 3.4, 95% CI; 1.2-9.8, P for interaction = 0.035).
The study, led by Mandy D. Müller, MSc (University Hospital Basel, Switzerland), was published in the May 2017 issue of Stroke.
One of Many Factors
To NVX, Ng pointed out that while complex vascular anatomy was indeed linked with a higher risk of DWI lesions with stenting, the proportion of patients with such lesions who had stroke symptoms was actually nonsignificantly higher with endarterectomy (6 of 49 among stented patients and 2 of 14 among endarterectomy patients). It is unclear, he noted, whether it was simply by chance that DWI hits following stenting did not affect more eloquent areas of the brain.
“The findings of this study are not surprising and were previously largely assumed by neurovascular physicians,” he indicated. “Difficult aortic arches to catheterize that may necessitate catheter exchanges and tortuous carotid arteries have been associated with increased complications with cerebral angiography, so logically the risk would extend to encompass any endovascular neurointerventions, such as carotid stenting. What is new in this study is the objective classification of aortic arches (Type 2 and 3) as well as internal carotid artery tortuosity > 60° as criteria that may favor CEA.”
But he pointed out that carotid anatomy is only one of many factors that should be considered when selecting a treatment. Other important factors that would favor stenting include previous CEA performed on the same artery in the past, history of neck irradiation, and better operator experience with stenting at the specific institution where the patient is being treated.
“An additional interesting finding in this study was that characteristics of the carotid plaque (degree, length of stenosis and ulceration) was not correlated to new DWI lesions after CAS in contrast to prior studies,” he noted. “Endovascular physicians could now argue that such features should not dissuade one from offering CAS in favor of CEA.”
“Future research targeted at identifying additional factors that would favor one treatment modality over the other would help in deciding the most appropriate procedure for each patient,” he added. “Possibilities may include looking at additional plaque characteristics such as degree of calcification on CT, presence of intraplaque hemorrhage on MRI, patient comorbidities such as diabetes control, heart disease/arrhythmia, and so on.”
Sources:
Müller MD, Ahlhelm FJ, von Hessling A. et al. Vascular anatomy predicts the risk of cerebral ischemia in patients randomized to carotid stenting versus endarterectomy. Stroke. 2017;Epub ahead of print.
Disclosures:
- Ng and Müller report no relevant conflicts of interest.
- Bonati has served on scientific advisory boards for Bayer.
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