INITIAL EXPERIENCE WITH INTRAVASCULAR ULTRASOUND IMAGING DURING CAROTID ENDARTERECTOMY

Background and Purpose To assess the feasibility of intravascular ultr asound imaging during carotid endarterectomy. Methods Intravascular ul trasound imaging was performed during carotid endarterectomy in eight patients using an over-the-wire catheter system with a 30-MHz ultrasou nd probe. In vitro studies were carried out before the intraoperative application, paying special attention to visualization of the wall lay ers of normal carotid arteries, structures of more or less diseased ve ssels, and surgically placed materials such as patch, suture material, and fibrin glue. Although intravascular ultrasound failed to distingu ish between intima and media in areas of normal intima, fibrotic and c alcified plaques were detected clearly. Dacron patch as well as suture s were identified as highly reflective structures. Results In seven of the eight patients studied, intravascular ultrasound yielded cross-se ctional images of good quality allowing identification of the vessel l ayers and the structures at the endarterectomy site. In all patients t he three layers of the vessel wall were clearly differentiated and the transition zone between the site of endarterectomy and the genuine ve ssel appeared smooth without intimal flaps or residual arterioscleroti c plaques. In one patient severe eccentric thickening of the media was detected in the distal internal carotid artery. Neither damage of the vessel layers by the shunt nor thrombus formation in the operating ar ea and the internal carotid artery were detected. Conclusions Intravas cular ultrasound lends itself as a potentially valuable method of qual ity control during carotid endarterectomy. The method seems to enable an accurate evaluation of the endarterectomy site and the search for r esidual plaques.