Filter-Protected versus Unprotected Carotid Artery Stenting: A Randomised Trial

Abstract

Background: Our aim was to determine whether filter protection reduces embolisation to the brain during carotid artery stenting (CAS). Methods: Thirty patients with symptomatic carotid artery stenosis ≧70% (North American Symptomatic Carotid Endarterectomy Trial) were randomly assigned to filter-protected or unprotected CAS. Diffusion-weighted magnetic resonance imaging (DWI) of the brain was performed before and at 3 time points after CAS. In a subset of patients, high-intensity transient signals on transcranial Doppler (TCD) were recorded with categorisation of emboli. Data were independently reviewed off-site. Results: There were no significant differences in mean age, proportion of octogenarians or presenting symptoms between the groups. On procedural DWI (1–3 and 24 h after stenting), there were 7/24 (29%) and 4/22 (18%) new lesions in protected and unprotected patients respectively (p = 0.38). At 30 days there were 9/33 (26%) and 4/33 (12%) lesions in protected and unprotected patients, respectively (p = 0.1). On TCD there were significantly more signals in total as well as particulate emboli during filter-protected CAS (426.5 and 251.3) than during unprotected CAS (165.2 and 92) – p = 0.01 and 0.03, respectively. Conclusions: Filter-protected CAS is associated with an increase in new lesions on DWI and significantly higher rates of total and particulate microembolisation on TCD than unprotected CAS. The clinical significance of these findings requires further study.

Characteristics of Ischemic Brain Lesions After Stenting or Endarterectomy for Symptomatic Carotid Artery Stenosis

“…Although previous nonrandomized studies reported higher proportions of patients with new DWI lesions after unprotected than after protected CAS, 2 small randomized studies previously have shown higher rates of DWI lesions after filter-protected than after unprotected stenting. 17,18 Our observation is in line with these findings and casts doubt on the beneficial effect of filter-type protection devices. 19 Volumes of individual DWI lesions were significantly smaller after CAS compared with CEA, resulting in no significant difference in total lesion volume per patient between treatment groups.…”

Impact of Silent Ischemic Lesions on Cognition following Carotid Artery Stenting

“…EPDs are designed to catch intraoperative microemboli produced during catheter manipulation and stenting placement, and their application has been shown to reduce perioperative stroke [30]. However, the use of EPDs may not reduce the occurrence of SILs on DWI [28,32]. Furthermore, the presence of debris captured by EPDs does not guarantee the avoidance of subsequent cerebral ischemic events [31], and the amount of procedure-related microembolic showers on transcranial ultrasound is not associated with the appearance of asymptomatic DWI-positive lesions [27].…”

Unprotected Carotid Artery Stenting in Symptomatic Patients with High-Grade Stenosis: Results and Long-Term Follow-Up in a Single-Center Experience

“…30 A higher rate of cerebral ischemic lesions on DWI associated with the use of protection devices has also been found. 31,32 Finally, it has been estimated that cerebral protection devices prevent only 25% of clinical embolisms. 33 Therefore, it is reasonable to question their usefulness.…”