Carotid artery occlusion following endarterectomy: evaluation by spectral analysis of Doppler ultrasound signals.

The clinical results of carotid endarterectomy are well documented, but there is little objective information on the incidence of postoperative occlusion. We have studied the postoperative patency of the internal and external carotid arteries using continuous wave Doppler ultrasound with spectral analysis (Spectrascribe BOC--Medishield). Seventy-nine patients who had had 89 endarterectomies during the past 5 years entered the study. The mean follow-up was 21 months. Fourteen patients had an occluded internal carotid artery of whom 4 had suffered an immediate postoperative stroke and 1 a delayed stroke: transient ischaemic attacks occurred in another 4 patients. Of the 60 patients with a patent internal carotid artery one suffered an immediate postoperative stroke and 2 a delayed stroke; 6 patients had recurrent transient ischaemic attacks. None of the 5 patients who had an external carotid endarterectomy developed postoperative symptoms, although there was occlusion in 2. The carotid artery was occluded in 4 of 43 completely asymptomatic patients. Thus, 18 per cent of all carotid endarterectomies and 9 per cent of asymptomatic patients in this series had postoperative occlusion of the carotid artery.