title: Extravascular application of an intravascular ultrasound (IVUS) catheter during carotid endarterectomy to verify distal ends of stenotic lesions.
abstract: BACKGROUND
  Intravascular ultrasound (IVUS) has been developed initially for intravascular imaging of coronary arteries to investigate vascular structures. We applied the IVUS catheter extravascularly to the cervical carotid arteries to obtain intra-operative ultrasound images during carotid endarterectomy (CEA). Intra-operative assessments of the distal ends of the stenotic lesions as well as pathological vascular structures are important, not only for exposing the lesions sufficiently but also for placing the shunt system safely.
  
  
  METHODS
  An IVUS catheter (3.2 French/30 MHz) was intra-operatively applied close to the outer surface of the cervical carotid arteries during CEA. Ultrasound transection vascular images were obtained in 33 consecutive patients (30 males and 3 females) with a mean age of 66.5 years.
  
  
  RESULTS
  In 32 of 33 cases, extravascular application of IVUS catheter before making arteriotomies correctly depicted the distal ends of the internal carotid artery (ICA) stenotic lesions as a thin layer of vascular wall [0.64 +/- 0.16 mm (mean +/- SD) compared with 1.66 +/- 0.42 mm for carotid plaque] with intravascular blood flow. Based on the IVUS findings, we were able to adequately expose the normal ICA portion distal to the stenotic lesion before making the arteriotomy even in cases with stenotic lesions at very high positions, and to insert shunts safely. Furthermore, the properties of lesions and blood flow were also verified. However, it was difficult to examine the far vascular wall.
  
  
  CONCLUSIONS
  Extravascular application of IVUS catheter is efficient for intra-operative evaluation of the distal end of the stenotic lesion especially in cases with stenotic lesions at very high positions and cases in whom pre-operative angiograms did not clearly demonstrate the distal end. The findings also demonstrate the properties of lesions and completeness of CEA.
authors.affiliation: Department of Neurosurgery, Neurological Institute, Tokyo Women's Medical University, Tokyo, Japan. tkawamata@nij.twmu.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Kawamata
authors.forename: Y
authors.initials: Y
authors.lastname: Okada
authors.forename: S
authors.initials: S
authors.lastname: Kondo
authors.forename: A
authors.initials: A
authors.lastname: Kawashima
authors.forename: Y
authors.initials: Y
authors.lastname: Tsutsumi
authors.forename: T
authors.initials: T
authors.lastname: Hori
mesh_terms: D000328:Adult; D000368:Aged; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D016894:Endarterectomy, Carotid; D004730:Endothelium, Vascular / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D012189:Retrospective Studies; D016896:Treatment Outcome; D018084:Ultrasonography, Interventional / Q000379:methods*