HEMODYNAMIC-EFFECTS OF CAROTID ENDARTERECTOMY BY MAGNETIC-RESONANCE FLOW QUANTIFICATION

Background and Purpose Blood flow fan be evaluated noninvasively using magnetic resonance phase-contrast flow quantification. The purpose of this prospective study was to assess the feasibility of this method a nd to evaluate the hemodynamic effects of carotid endarterectomy. Meth ods Volumetric flow rates and peak systolic velocities of the internal and common carotid and the vertebral arteries were measured by magnet ic resonance flow quantification. Sixteen patients undergoing 18 endar terectomies had complete how data recorded preoperatively and 3 days a fter surgery. Results The inverse correlation between the angiographic stenosis degree and the preoperative flow rate in the corresponding i nternal carotid artery was highly significant (r= -.69, P<.001). After endarterectomy, the mean flow in the ipsilateral internal carotid art ery improved from 143 to 233 mL/min (P<.001). The mean peak systolic v elocity increased from 23 to 37 cm/s (P<.001). No significant changes were seen in the contralateral carotid or the vertebral arteries. The mean total blood flow improved by 81 mL/min (P=.08). In the severely s tenosed bifurcations (70% to 99%, n=11), the flow rate improved by 106 mL/min and in the moderately (30% to 69%, n=4) or mildly (<30%, n=3) stenosed bifurcations by 63 mL/min. If the contralateral carotid arter y was occluded or severely stenosed, the improvement was 164 mL/min. C onclusions Magnetic resonance flow quantification provides a useful to ol for the follow-up of the hemodynamic effects of carotid endarterect omy. Our results indicate that surgery is followed by a significant in crease of blood flow in the ipsilateral carotid artery and that there appear to be differences in flow increase between subgroups of patient s with different degrees of stenosis.