Technical limitations of carotid filter embolic protection devices

Improved carotid artery stenting (CAS) results are credited to the development of embolic protection devices (EPDs). Reported are outcomes and technical failures of two classes of EPDs: distal balloon occlusion and distal filtration. We present a retrospective review of 206 CAS procedures from April 2001-September 2005. Filters (AccuNet, Angioguard, Filterwire, or Emboshield) were used in 98 cases (48%), distal balloon occlusion (PercuSurge) in 94 (46%), and no protection in 14. Data include demographics and procedural records. Mean age was 70 years (76% men, 24% women). At 30 days, there were no deaths, no myocardial infarctions, two major ipsilateral strokes (1%), two minor posterior strokes (1%), four transient ischemic attacks (2%), and one major access site complication (0.5%). Major neurologic events were equally divided between balloon occlusion and filters. Mean balloon occlusion time was 12 min, with only two patients (2%) manifesting reversible neurologic intolerance during flow arrest. In the last 100 cases, filter devices were preferentially used due to preserved antegrade flow. However, 11 cases (11%) necessitated intraoperative switching to balloon occlusion because of either extreme tortuosity or severe stenosis of the target lesion precluding passage of the filter element. CAS-specific equipment has improved procedural results. Despite theoretic advantages of filter EPDs, up to 10% of lesions are either too narrow or tortuous to allow safe passage of the filter element. Switching to a distal balloon occlusion system, which is well tolerated, may be preferred to unprotected predilation. Practitioners of CAS should be versed in both.