Initial experience with intravascular ultrasound imaging during carotid endarterectomy.

BACKGROUND AND PURPOSE To assess the feasibility of intravascular ultrasound imaging during carotid endarterectomy. METHODS Intravascular ultrasound imaging was performed during carotid endarterectomy in eight patients using an over-the-wire catheter system with a 30-MHz ultrasound probe. In vitro studies were carried out before the intraoperative application, paying special attention to visualization of the wall layers of normal carotid arteries, structures of more or less diseased vessels, and surgically placed materials such as patch, suture material, and fibrin glue. Although intravascular ultrasound failed to distinguish between intima and media in areas of normal intima, fibrotic and calcified plaques were detected clearly. Dacron patch as well as sutures were identified as highly reflective structures. RESULTS In seven of the eight patients studied, intravascular ultrasound yielded cross-sectional images of good quality allowing identification of the vessel layers and the structures at the endarterectomy site. In all patients the three layers of the vessel wall were clearly differentiated and the transition zone between the site of endarterectomy and the genuine vessel appeared smooth without intimal flaps or residual arteriosclerotic 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 area and the internal carotid artery were detected. CONCLUSIONS Intravascular ultrasound lends itself as a potentially valuable method of quality control during carotid endarterectomy. The method seems to enable an accurate evaluation of the endarterectomy site and the search for residual plaques.