[Hemodynamic assessment of cerebrovascular circulation using transcranial Doppler ultrasound in patients with carotid stenosis].

Transcranial Doppler-ultrasound (TCD) is a new non-invasive technique which renders continuous monitoring of the rate of flow in the major intracerebral arteries possible. The method appears, therefore, to be attractive for perioperative monitoring of patients submitted to operation on account of carotid stenosis. Seventeen patients were included in this preliminary investigation. These patients were submitted for thromboarterectomy of the internal carotid artery. Preoperatively the average flow rate (Vmean) in the ipsilateral medial cerebral artery measured at rest was 54 cm/second (range 34-94) as compared with 57 cm/second (range 32-86) in the contralateral medial cerebral artery. During occlusion, Vmean in the ipsilateral medial cerebral artery decreased momentarily, on an average 35% (p less than 0.001), and returned to the preoperative level after reopening of the internal carotid artery. Corresponding but no significant changes were observed in the pulsatile index. The preliminary experience suggests that TCD is scarcely useful as a diagnostic method in individual cases but that it is well suited for continuous monitoring of changes in cerebral circulating during surgery on the internal cerebral artery. Further assessment of the technique is necessary before the method can be employed routinely, mainly on account of the great interindividual scatter.