TRANSCRANIAL DOPPLER IN 178 PATIENTS BEFORE, DURING, AND AFTER CAROTID ENDARTERECTOMY

From July 1991 to March 1995, 178 patients who underwent 198 carotid s urgical repairs were investigated preoperatively, intraoperatively, an d postoperatively by transcranial Doppler sonography (TCD). Preoperati ve TCD evaluation showed stenosis of the middle cerebral artery (MCA) in 4 patients (2.2%), siphon stenosis in 3 (1.6%), incomplete circle o f Willis in 23 (12.9%), a decrease of mean blood flow velocity more th an 70% of the basal value during digital common carotid compression in 31 (17.9%), and a critical reduction of vasomotor reactivity (no sign ificant increase of mean blood flow velocity in the MCA during breath- holding test) in 34 (19.1%). Nine patients (5%) had surgery without pr eoperative angiography. In those patients the indication for surgery w as based on color Doppler imaging and TCD investigations. Ninety surgi cal procedures were carried out under general anesthesia and 108 under locoregional anesthesia. in 37 surgeries (31.7%) a shunt was inserted : The use of a shunt was based on a decrease of mean blood flow veloci ty in the MCA below 50% of the basal value under general anesthesia or loss of consciousness combined with a decrease of mean blood flow vel ocity in the MCA higher than 70% of the basal value when locoregional anesthesia was employed. Intraoperative TCD monitoring showed a decrea se of mean blood flow velocity in the MCA due to shunt malfunction in (8.3%) of 36 surgeries, turbulence of blood flow during declamping in 79 procedures (39.8%), and microembolic events in 10 patients (5%) tha t were related to one transient and one permanent neurological deficit . Another permanent deficit occurred in a patient without TCD signs. A fter surgery, TCD reliably detected an early asymptomatic occlusion of the carotid artery, hyperperfusion syndrome in 12 (6.0%), and an incr ease of vasomotor reactivity in 10(29.4%) of 34 surgeries.