Cerebral Embolic Lesions Detected With Diffusion-Weighted Magnetic Resonance Imaging Following Carotid Artery Stenting: A Meta-Analysis of 8 Studies Comparing Filter Cerebral Protection and Proximal Balloon Occlusion

Study Questions:

What is the comparative efficacy of filter embolic protection and proximal balloon occlusion systems in preventing embolization during carotid artery stenting (CAS), as detected by diffusion-weighted magnetic resonance imaging (DW-MRI)?


The authors performed a meta-analysis that included eight studies (n = 357 patients), of which five were randomized. The primary endpoint of the study was the incidence of new ischemic lesions detected on MRI.


Following CAS, the incidence of new ischemic lesions/patient detected by DW-MRI was significantly lower in the proximal balloon occlusion group (effect size [ES], −0.43; 95% confidence interval [CI], −0.84 to −0.02; I2 = 70.08; Q = 23.40). Furthermore, following CAS, the incidence of lesions at the contralateral site was significantly lower in the proximal protection group (ES, −0.50; 95% CI, −0.72 to −0.27; I2 = 0.00; Q = 3.80).


The authors concluded that use of proximal balloon occlusion compared with filter cerebral protection is associated with a reduction in the amount of CAS-related brain embolization.


The results of this study corroborate the clinical experience with proximal occlusion demonstrating a very low complication rate among patients undergoing carotid stenting with these devices (J Am Coll Cardiol 2010;55:1661-7). Ideally, one would like to see clinical data comparing proximal occlusion versus filters, but the low complication rate of CAS makes such trials unlikely. Based on the surrogate endpoints, as well as published clinical experience, proximal occlusion devices should be preferentially considered (if technically feasible) in patients undergoing CAS.

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