Hemodynamic considerations during carotid endarterectomy

To evaluate the hemodynamic and angiographic characteristics of patients undergoing carotid endarterectomy, we reviewed the medical records, angiograms, transcranial Doppler ultrasound data, and EEGs of 42 consecutive patients having 44 carotid endarterectomies. Significant (p < 0.0002) changes in the peak systolic velocity of the middle cerebral artery ipsilateral to the side of surgery (iMCAFV) occurred with anesthesia, carotid clamping, shunting, and the release of clamps. Thirteen percent of patients with collateral flow toward the side of surgery and 57% of those with flow away from the operated side had a drop in iMCAFV exceeding 50% of the baseline value (p = 0.054); the presence of a <70% ipsilateral internal carotid artery stenosis was also correlated with a similar decrease in iMCAFV (p = 0.01). There was no correlation between systolic blood pressure changes and iMCAFV in patients who were not shunted. This information may be useful in guiding intraoperative decision-making.