Effect of the distal-balloon protection system on microembolization during carotid stenting

Background-The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting (CAS). We sought to determine the effect of this system on the frequency of Doppler-detected microembolic signals (MES) during CAS. Methods and Results-Using transcranial Doppler, we compared the frequency of MES during CAS in 2 groups: 39 patients without distal protection and 37 who used the distal-balloon protection system (GuardWire). There were no significant differences in the clinical or angiographic characteristics between the 2 groups. Three phases with increased MES counts were identified during unprotected CAS, these were stent deployment, predilation, and postdilation (75 +/- 57, 32 +/- 36, and 27 +/- 25 METS, respectively). The distal-balloon protection significantly reduced the frequency of MES during CAS (MES counts: 164 +/- 108 in the control versus 68 +/- 83 in the protection group; P=0.002), particularly during these 3 phases. MES in the protection group were detected predominantly during sheath placement, guidewire manipulation, and distal-balloon deflation. Conclusion-Three phases with increased MES counts were identified during unprotected CAS (eg, stent deployment, predilation, and postdilation). The distal-balloon protection system significantly reduced the frequency of MES during CAS, particularly during these 3 phases.