The value of 3D-CT angiographic assessment prior to carotid stenting.

OBJECTIVE: Anatomic suitability for carotid artery stenting (CAS) is determined by arteriography, but this has a discrete stroke risk. We evaluated the use of multidetector CT angiography with three-dimensional reconstruction (3D-CTA) as a noninvasive screening tool for prospective CAS patients.
METHODS: Between 2003 and 2006, 90 CAS procedures were performed by vascular surgeons at our institution. At the discretion of the operating surgeon, 59 of the potential candidates for CAS underwent screening 3D-CTA of the aortic arch and carotid arteries. Results were used in patient selection and then analyzed retrospectively to determine clinical utility.
RESULTS: Analysis of 3D-CTA data by the operating surgeon allowed stratification of patients into four groups: (1) appropriate for CAS via femoral approach (n = 37, 63%); (2) appropriate for CAS with transcervical access due to adverse arch anatomy (n = 2, 3%); (3) borderline anatomy for CAS (n = 5, 9%); or (4) not appropriate anatomy for CAS (n = 15, 25%). Group 1 had 100% technical success with one minor stroke. Group 2 had successful transcervical CAS without stroke. Group 3 patients underwent arteriography but CAS was aborted in four out of five cases for the same reason that had been identified by 3D-CTA (internal carotid artery [ICA] tortuosity n = 2, ICA string sign with distal disease n = 2). The one failure in group 3 was the result of a previously placed common carotid stent extending into an already unfavorable aortic arch. Group 4 patients underwent endarterectomy (n = 7) or continued medical management (n = 8) instead of CAS (without arteriography) because of the following reasons, cited alone or in combination: common carotid tandem stenosis n = 5, difficult arch anatomy n = 2, ICA tortuosity n = 2, extreme lesion calcification or length n = 4, ICA string sign or occlusion n = 3, concomitant intracranial disease n = 2, and stenosis overestimated by duplex n = 3. The overall 30-day stroke rate, on an intention to treat basis, for patients that underwent preprocedural 3D-CTA was 2.3% (one major [NIH stroke scale >3] and one minor stroke).
CONCLUSIONS: In our initial experience, 3D-CTA reconstruction of the aortic arch and carotid arteries significantly influenced the plan for CAS in 37% of patients. Patients with clear anatomic contraindications to CAS can be excluded without the risks of arteriography. 3D-CTA further facilitates the CAS procedure by anticipating potential procedural. The cost-effectiveness and potential impact of this imaging modality on CAS outcomes deserve further study.