Intraoperative use of a new angle-independent Doppler system to measure arterial velocities after carotid endarterectomy.

OBJECTIVE

The purpose of this study was to assess the intraoperative use of a new angle-independent ultrasound scan device (EchoFlow [EF]) in measurement of carotid artery velocities after endarterectomy. Specifically, the purpose was to determine the reproducibility of velocity measurements obtained with EF and to compare these measurements with the velocity measurements obtained with duplex ultrasound scan.

METHODS

Velocity measurements of the common, internal, and external carotid arteries were performed by the operative surgeon with EF in 65 consecutive patients after carotid endarterectomy (36 female, 29 male; mean age, 71 years). Three velocity measurements were obtained from each of the arteries with EF and compared with the velocity measurements obtained with duplex ultrasound scan performed by a radiologist.

RESULTS

Velocity measurements obtained with the EF device were reproducible in the common, internal, and external carotid arteries (intrapatient correlation coefficients, 0.95, 0.96, and 0.95, respectively). Seventy-five percent of common, 88% of internal, and 78% of external carotid velocity measurements obtained with the angle-independent ultrasound scan device were within 25 cm/s of the velocities measured with duplex ultrasound scan. The mean differences in velocity measurements between EF and duplex scan were -12 cm/s in the common, -8 cm/s in the internal, and -11 cm/s in the external carotid arteries. Differences between the EF device and duplex scan velocity measurements correlated with increasing arterial velocities in each of the three arteries measured (P <.05).

CONCLUSION

Reproducible measurements of carotid artery velocity may be obtained with a new angle-independent Doppler system after endarterectomy. Most measurements obtained with the EF system are clinically comparable with those obtained with standard duplex ultrasound scan. This novel low-cost device may be useful in the intraoperative assessment of hemodynamic adequacy of carotid endarterectomy.