Predicting the effect of carotid artery occlusion during carotid endarterectomy: comparing transcranial doppler measurements and cerebral angiography.
OBJECTIVE
We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography.


METHODS
Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and group 3 on the ipsilateral posterior communicating artery. Continuous middle cerebral artery FVm and electroencephalographic monitoring were performed in 45 patients during carotid endarterectomy.


RESULTS
Clamped FVm was lowest in group 3 at 17+/-9 cm/s versus 36+/-16 and 33+/-11 cm/s for groups 1 and 2 (P<0.01). FVm values in groups 1 and 2 were similar. There was significant cerebral arterial vasodilation in group 3 patients on the basis of a pulsatility index of 0.38+/-0.15. The maximum FVm after clamp release was similar among the 3 groups. Normalized blood flow velocity 1 minute before release of the clamp was increased from the minimum flow velocity after clamping only in group 1 and 2 patients.


CONCLUSIONS
The ipsilateral posterior communicating artery is a minor collateral pathway during acute carotid occlusion that contributes little to the collateral flow if there is a functional anterior communicating artery. Collateral flow through the middle cerebral artery is not recruited during occlusion in group 3 patients. The reperfusion FVm transient is independent of the primary collateral pathway. Documentation of functional collateral pathways on the basis of Doppler or angiographic examination may be advantageous in future studies since it can provide the basis for comparison among studies.
Doblar
D D
DD
Departments of Anesthesiology, Biomedical Engineering, University of Alabama at Birmingham ddoblar@ms.jt.anes.uab.edu
Plyushcheva
N V
NV
Jordan
W
W
McDowell
H
H
D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001783:Blood Flow Velocity / Q000502:physiology; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002533:Cerebral Angiography; D003097:Collateral Circulation / Q000502:physiology; D004569:Electroencephalography; D004691:Endarterectomy; D005544:Forecasting; D006801:Humans; D016343:Monitoring, Intraoperative / Q000379:methods; D012212:Rheology; D014463:Ultrasonography