Altered flow territories after carotid stenting and carotid endarterectomy

The hemodynamic effects of carotid angioplasty with stent placement (CAS) on the collateral blood supply and on the regional cerebral blood flow (rCBF) have not been established. Recently, arterial spin-labeling (ASL) magnetic resonance imaging (MRI) has been introduced as the first method to quantify the actual territorial contribution of individual collateral arteries as well as to noninvasively measure rCBF. This study investigated alterations in flow territories and rCBF in patients with symptomatic internal carotid artery (ICA) stenosis and compared them with healthy control subjects. In addition, we investigated whether possible differences in flow territories and rCBF were present between patients undergoing CAS and patients undergoing carotid endarterectomy (CEA).

The study included 24 consecutive patients (15 men and 9 women; age 67+/-9 years) with symptomatic ICA stenosis. CAS was performed in 12 patients, and 12 patients underwent CEA. Flow territory mapping and rCBF measurements were performed with ASL MRI before intervention and 1 month after. The control group consisted of 40 subjects (25 men and 15 women; age 67+/-8 years).

The flow territory of the ipsilateral ICA in patients with ICA stenosis was smaller, and the territories of the contralateral ICA and vertebrobasilar arteries were larger compared with control subjects (P<.05). After CAS, rCBF in the ipsilateral hemisphere increased from 60.2+/-16.9 mL/(min.100 g) to 68.9+/-9.2 mL/(min.100 g) (P<.05). Differences in flow territories and rCBF between patients and control subjects disappeared after CAS. Changes in flow territories and rCBF were similar in patients who underwent CAS or CEA.

CAS results in a normalization of the territorial distribution and rCBF, as assessed by ASL MRI. The degree of improvement is similar to that seen after CEA.