title: Flow impairment during protected carotid artery stenting: impact of filter device design.
abstract: OBJECTIVE
  To investigate the impact of filter design on blood flow impairment in the internal carotid artery (ICA) among patients undergoing carotid artery stenting (CAS) using filter-type emboli protection devices (EPD).
  
  
  METHODS
  Between July 2003 and March 2007, 115 filter-protected CAS procedures were performed at an academic institution in 107 consecutive patients (78 men; mean age 68 years, range 38-87). The Angioguard, FilterWire EZ, and Spider filters were used in 68 (59%), 32 (28%), and 15 (13%) of cases, respectively. Patient characteristics, procedural and angiographic data, and outcomes were prospectively entered into an electronic database and reviewed retrospectively along with all angiograms.
  
  
  RESULTS
  Flow impairment while the filter was in place was observed in 25 (22%) cases. The presumptive reason of flow impairment was filter obstruction in 21 (18%) instances and flow-limiting spasm at the level of the filter in 4 (4%). In all cases, flow was restored after retrieval of the filter. Flow obstruction in the ICA occurred more frequently with Angioguard (22/68; 32.3%) than with FilterWire EZ (2/32; 6.2%) or Spider (1/15; 6.7%; p = 0.004). No flow occurred in 13 (19%) procedures, all of them protected with Angioguard; no patient treated with other devices experienced this event (p = 0.007). Two (8.0%) strokes occurred in procedures associated with flow impairment, while 1 (1.1%) event was observed in the presence of preserved flow throughout the intervention (p = 0.11).
  
  
  CONCLUSIONS
  Flow impairment in the ICA during filter-based CAS is common and related to the type of filter used.
authors.affiliation: Andreas Gruntzig Cardiovascular Catheterization Laboratories, Department of Cardiology, University Hospital, Raemistrasse 100, Zurich, Switzerland. marco.roffi@usz.ch
authors.forename: Marco
authors.initials: M
authors.lastname: Roffi
authors.forename: Matthias
authors.initials: M
authors.lastname: Greutmann
authors.forename: Urs
authors.initials: U
authors.lastname: Schwarz
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Luscher
authors.forename: Franz R
authors.initials: FR
authors.lastname: Eberli
authors.forename: Beatrice
authors.initials: B
authors.lastname: Amann-Vesti
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D000800:Angioplasty, Balloon; D000925:Anticoagulants / Q000627:therapeutic use; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal; D016893:Carotid Stenosis / Q000601:surgery*; D016009:Chi-Square Distribution; D005260:Female; D005374:Filtration / Q000295:instrumentation*; D006801:Humans; D020766:Intracranial Embolism / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D012189:Retrospective Studies; D015607:Stents; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants