Objective: To emphasize the integrated use of transcranial Doppler ultrasonography (TCD) in the management of internal carotid artery (ICA) closure.
Methods: Thirty-three patients being considered for ICA closure underwent TCD assessment, vasomotor reserve testing/estimation, and carotid artery test occlusion with concomitant middle cerebral artery (MCA) blood velocity (V(MCA)) monitoring, including calculation of the MCA pulsatility index. Twelve of these patients proceeded to undergo ICA sacrifice. Sequential TCD sonograms guided their postoperative treatment.
Results: ICA aneurysms and neck neoplasms affected the TCD results and vasomotor reserve insignificantly, whereas carotid-cavernous fistulae induced characteristic circulatory alterations. The 10 subjects who tolerated ICA sacrifice hemodynamically all showed an initial decrease in the ipsilateral V(MCA) to > or =60% of the preocclusion value and a progressively decreasing MCA pulsatility index during carotid artery test occlusion. The two patients who developed hemodynamic cerebral infarctions exhibited a decrease in V(MCA) to <60% and a MCA pulsatility index that remained stable after a vast initial reduction. Postoperative hypervolemic and hypertensive support was safely titrated in all patients who received postoperative TCD surveillance, providing an ipsilateral V(MCA) of > or =80% of the preocclusion value. ICA closure permanently altered the cerebral circulatory pattern.
Conclusion: The hemodynamic outcome of ICA sacrifice can be correctly predicted by using the TCD occlusion test. TCD provides the means to titrate the extent of postoperative hypervolemic/hypertensive support.