Restenosis after carotid artery stenting using a specific designed ultrasonographic protocol

Background: Nowadays, the number of patients undergoing carotid artery stenting (CAS) is increasing rapidly, and these patients require follow-up to monitor the patency of the device and the potential development of an in-stent restenosis (ISR).

Methods: Patients undergoing CAS at our institution underwent duplex ultrasound (DUS) at 6 months, 12 months, and yearly thereafter, using a prespecified protocol. Restenosis was defined as a more than 50% diameter-reducing stenosis. Patients with DUS-diagnosed restenosis underwent carotid computerized tomography angiography (CTA) to confirm the presence of ISR. The frequency of restenosis was calculated by Kaplan-Meier survival estimates and was compared during a 2-year follow-up period. Interactions between restenosis and baseline variables were assessed using odds ratio.

Results: Between August 2007 and March 2012 were performed 100 procedures in 96 patients, with a median age of 72.9 years. The mean duration of follow-up was 29.2 months (±8.4). Restenosis occurred in 6 carotid arteries. The Kaplan-Meier estimate for the frequency of restenosis in 2 years was 6.0% and for severe restenosis was 3.0%. There were no occlusions. Diabetic patients seem to have a higher risk of ISR (OR=3.23, 95% CI .55-18.9). Carotid CTA was in agreement with the degree of stenosis estimated by DUS in all cases.

Conclusions: Our results, using a DUS protocol and a specific peak systolic velocity threshold, showed that the frequency of restenosis at 2 years after CAS is 6.0% and so that CAS is probably a durable revascularization procedure. We emphasize the diagnostic agreement achieved between DUS and carotid CTA.