Revascularization of the external carotid artery

Carotid artery stenting has increased risk of external carotid artery occlusion compared with carotid endarterectomy

OBJECTIVE

The external carotid artery (ECA) can be an important source of cerebral blood flow in cases of high-grade internal carotid artery stenosis or occlusion. However, the treatment of the ECA is fundamentally different between carotid endarterectomy (CEA) and carotid artery stenting (CAS). CEA is routinely associated with endarterectomy of the ECA, whereas CAS excludes the ECA from direct flow. We hypothesize that these differences make ECA occlusion more common after CAS. Further, the impact of CAS on blood flow into the ECA is interesting because the flow from the stent into the ECA is altered in a way that may promote local inflammation and may influence in-stent restenosis (ISR). Thus, our objective was to use our institutional database to identify whether CAS increased the rate of ECA occlusion and, if it did, whether ECA occlusion was associated with ISR.

METHODS

Patients undergoing CAS or CEA from February 2007 to February 2012 were identified from our institutional carotid therapy database. Preoperative and postoperative images of patients who followed up in our institution were included in the analysis of ECA occlusion and rates of ISR.

RESULTS

There were 210 (67%) CAS patients and 207 (60%) CEA patients included in this analysis. Despite CAS patients being younger (68 vs 70 years), having shorter follow-up (12.5 vs 56.2 months), and being more likely to take clopidogrel (97% vs 35%), they had an increased rate of ECA occlusion (3.8%) compared with CEA patients (0.4%). CAS patients who went on to ECA occlusion had an increased incidence of prior neck irradiation (50% vs 15%; P = .03), but we did not identify an association of ECA occlusion with ISR >50%.

CONCLUSIONS

Whereas prior publications have identified increased rates of external carotid stenosis, this is the first demonstration of increased ECA occlusion after CAS. However, ECA occlusion is uncommon (∼4%) and did not have an association with ISR >50%. Future work modeling ECA flow patterns before and after CAS will be used to further test this interaction.

External carotid endarterectomy for amaurosis fugax in the presence of internal carotid artery occlusion

Two patients with occlusion of the internal carotid artery who were experiencing repeated episodes of transient monocular blindness in the ipsilateral eye were successfully treated with external carotid endarterectomy. The mechanisms for the production of symptoms in the presence of an internal carotid occlusion are discussed, including the anatomical pathways for embolization through collaterals between the internal and external carotid arteries. The indications, technique and results of external carotid endarterectomy are reviewed.