The fate of residual defects following carotid endarterectomy detected by early postoperative duplex ultrasound.

The purpose of this study is to evaluate the results of color-flow duplex ultrasound (CFD) soon after carotid endarterectomy (CEA) to determine the incidence of residual abnormalities and their effect on subsequent outcome and management. We reviewed 318 consecutive CEAs performed over a 48 month-period. Of these, 206 were followed up with CFD, 195 prior to discharge and 11 at first follow-up (within 9 weeks). Patients (43) followed up with only oculoplethysmography (OPG) or those with no OPG or CFD (69) were excluded from the study. All CEAs were performed under general anesthesia with routine shunting and patch angioplasty. Twelve of the 206 studies (5.8%) were abnormal. Two patients with an abnormal CFD sustained perioperative stroke, both of whom had distal intimal lesions of > 60% diameter stenosis by velocity criteria. Four patients had > 60% stenosis and were reoperated upon to correct technical errors. The remaining 6 patients are asymptomatic. Four had residual lesions of < 60% stenosis, three of which have returned to normal on subsequent CFD. Two residual lesions had > 60% stenosis; one returned to normal by CFD and the other remains abnormal at 10 months. In the group of 192 normal postoperative CFD studies, there were no strokes, deaths, or redo procedures (0%, 95% confidence interval 0% to 1.54%) compared with a combined 50% rate (6 of 12) of either stroke (2 of 12) or redo procedure (4 of 12) when the postoperative CFD was abnormal (95% confidence interval 22.3% to 77.7%, P < 0.0001). During the study period the CEA stroke rate was 0.9% (3 of 318), with a combined stroke-mortality rate of 1.3% (4 of 318). Early postoperative CFD identified residual abnormalities in 5.8% of carotid endarterectomies despite a low overall stroke mortality rate. One half of these abnormalities resulted in stroke or required operative correction. Colorflow duplex ultrasound is useful in identifying residual abnormalities following CEA and should be considered for intraoperative use.