Transcranial Doppler ultrasonography-guided management of internal carotidartery closure

OBJECTIVE: To emphasize the integrated use of transcranial Doppler ultrason ography (TCD) in the management of internal carotid artery (ICA) closure. METHODS: Thirty-three patients being considered for ICA closure underwent T CD assessment, vasomotor reserve testing/estimation, and carotid artery tes t occlusion with concomitant middle cerebral artery (MCA) blood velocity (V -MCA) monitoring, including calculation of the MCA pulsatility index. Twelv e of these patients proceeded to undergo ICA sacrifice. Sequential TCD sono grams guided their postoperative treatment. RESULTS: ICA aneurysms and neck neoplasms affected the TCD results and vaso motor reserve insignificantly, whereas carotid-cavernous fistulae induced c haracteristic circulatory alterations. The 10 subjects who tolerated ICA sa crifice hemodynamically all showed an initial decrease in the ipsilateral V -MCA to greater than or equal to 60% of the preocclusion value and a progre ssively decreasing MCA pulsatility index during carotid artery test occlusi on. The two patients who developed hemodynamic cerebral infarctions exhibit ed a decrease in V-MCA to <60% and a MCA pulsatility index that remained st able after a vast initial reduction. postoperative hypervolemic and hyperte nsive support was safely titrated in all patients who received postoperativ e TCD surveillance, providing an ipsilateral V-MCA of greater than or equal to 80% of the preocclusion value. ICA closure permanently altered the cere bral circulatory pattern. CONCLUSION: The hemodynamic outcome of ICA sacrifice can be correctly predi cted by using the TCD occlusion test. TCD provides the means to titrate the extent of postoperative hypervolemic/hypertensive support.