[Reconstruction of brain-supplying arteries with bilateral monitoring by transcranial Doppler ultrasound--new aspects for technical surgical procedures].

From January to June 1994 reconstruction of 61 internal carotid arteries (ICA) with cerebral monitoring using bilateral transcranial Doppler sonography in the Clinic of Vascular Surgery Charité was performed. Recording of the maximal mean blood flow velocity in both middle cerebral arteries (MCA) was performed intraoperatively. After clamping of ICA flow velocity in the ipsilateral MCA decreased immediately but recovered within short time in 60% of our patients (Vmean > 25 cm/s). Based on the reaction of the contralateral MCA 3 types were differentiated: 1) Vmean of the contralateral side changed contrary to the ipsilateral side (compensation, "scissors type"). 2) The contralateral side did not react ("indifferent type"). 3) The contralateral side changed parallel to the ipsilateral side ("parallel type"). In 62% of our patients the operative strategy was influenced by transcranial Doppler monitoring: in 35% of cases the operative reconstruction was performed without intraluminal shunting, in 19% of cases the position of the intraluminal shunt was corrected, in 8% of cases the blood pressure was increased. Doppler signals due to emboli were registered in 43% of our patients. These patients did not show any new neurologic signs and symptoms. In one patient who developed a neurological deficit during the postoperative phase, emboli signals were recorded during a period of 30 minutes. Bilateral transcranial Doppler monitoring, especially in patients with contralateral high-grade stenoses or occlusions of the ICA, is a useful method for intraoperative cerebral monitoring. We recommend its application on a wide scale.