title: Impact of head movements on morphology and flow in the internal carotid artery after carotid angioplasty and stenting versus endarterectomy.
abstract: OBJECTIVE
  Because stents can cause vessel angulation during movement, we hypothesized that internal carotid artery (ICA) stents might lead to alterations of cerebropetal blood flow. This study assessed three-dimensional anatomy and volumetric flow rate (VFR) in the ICA in various head positions by comparing patients treated with carotid angioplasty and stenting (CAS) with patients treated with carotid endarterectomy (CEA).
  
  
  METHODS
  Three-dimensional time-of-flight magnetic resonance angiography and magnetic resonance flow quantification were performed on six subjects after CAS (median age, 70 years) and on six subjects after CEA (median age, 67 years). All investigations were performed in five head positions: neutral, bent forward, bent backward, and turned to the treated, ipsilateral side and to the contralateral side. Maximum-intensity projection reconstructions were obtained to measure maximal angulation of the ICA in the forward, backward, ipsilateral, and contralateral positions compared with neutral. Subsequently, the plane perpendicular to the ICA, 1 cm distal to the stent or 4 cm distal to the carotid bifurcation (CEA patients), was established. The VFR through this plane was measured for each position, and the forward, backward, ipsilateral, and contralateral positions were compared with neutral.
  
  
  RESULTS
  In CAS patients, there was a median change in ICA angulation of +10.2 degrees (interquartile range, +7.3 degrees to +17.9 degrees ) in the forward position, compared with +0.2 degrees (-1.0 degrees to +2.4 degrees ) in CEA patients ( P = .016). In all other head positions, there was no statistically significant difference in angulation change. There was no statistically significant difference in VFR change between groups in any of the head positions tested.
  
  
  CONCLUSIONS
  There was a significant increase in ICA angulation in CAS patients if the head was bent forward; this was not observed in CEA patients. This angulation change did not lead to significant acute changes in cerebropetal blood flow, but it might have chronic effects not yet tested.
authors.affiliation: Department of Interventional Radiology, St. Antonius Hospital, Koekoekslaan 1, 3435 CM Nieuwegein, The Netherlands. j.a.vos@antonius.net
authors.forename: Jan Albert
authors.initials: JA
authors.lastname: Vos
authors.forename: A W Floris
authors.initials: AW
authors.lastname: Vos
authors.forename: Matteus A M
authors.initials: MA
authors.lastname: Linsen
authors.forename: J Tim
authors.initials: JT
authors.lastname: Marcus
authors.forename: Timotheus Th C
authors.initials: TT
authors.lastname: Overtoom
authors.forename: Jos C
authors.initials: JC
authors.lastname: van den Berg
authors.forename: Willem
authors.initials: W
authors.lastname: Wisselink
mesh_terms: D000368:Aged; D000800:Angioplasty, Balloon; D002343:Carotid Artery, Internal / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000601:surgery / Q000628:therapy*; D016894:Endarterectomy, Carotid; D005260:Female; D006257:Head / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D011184:Postoperative Period; D012039:Regional Blood Flow; D015607:Stents