Incidence and Outcome of Filter Occlusion during Carotid Artery Stent Procedure

Recent reviews of device-specific complications using neuroprotection have addressed technical difficulties during delivery as well as adverse outcomes, intraoperative and 30-day. Little has been written, however, regarding the relevance of filter occlusion during the carotid stent procedure. A retrospective review was conducted of patients undergoing carotid artery stent procedures using a variety of neuroprotection devices from 2003 to 2007. Prospective databases from two institutions were examined for incidence and management of filter occlusions during procedures as well as adverse neurological events (intraoperative and 30-day) associated with filter occlusion. There were 283 carotid artery stent procedures performed on 256 patients (163 male, 93 female): 177 (62.5%) arteries were asymptomatic and 106 were symptomatic. Neurological adverse events occurred in six patients (2.1%); three of these resolved completely at 72 hr. Neuroprotection was used in 95% of all patients, and filters were used in 221 stent procedures: Boston Scientific Filter Wire (n = 81), Guidant Accunet (n = 100), Angioguard (n = 17), and Abbot Emboshield (n = 23). Filter occlusion occurred in 11 patients (4.9%) in whom this form of neuroprotection was employed: Angioguard (n = 5), Accunet (n = 2), Emboshield (n = 2), and EPI Filter wire (n = 2). Two of the 11 patients with filter occlusions suffered a neurological event. There was no correlation between filter occlusion and gender, symptoms, stent, or filter type (p > 0.05). Filter occlusion was managed with export catheter-directed aspiration in seven patients and with prompt filter retrieval in five patients. Filter occlusion is an infrequent event that does not appear to be filter-specific and can be managed successfully by catheter-directed aspiration or filter retrieval. The majority of patients with filter occlusion do not suffer from atheroemboli as a result of this occlusion.