[Extra- and intracranial Doppler ultrasound. Evaluation of patients with surgical anastomosis of the arteria temporalis superficialis superficialis and arteria cerebri media].

During a mean postoperative period of 16 months, 51 patients who had received an extracranial-intracranial (EC-IC) arterial bypass were examined by means of transcranial and extracranial Doppler ultrasound, with the following results: the flow velocities of the middle cerebral artery (MCA) are postoperatively significantly lower than in normal control subjects. No differences were seen if the MCA was supplied via the EC-IC bypass or via any "natural" collateral vessels. In 32 cases, blood supply of the MCA artery was provided via the EC-IC bypass. In another 13 cases the MCA was supplied via the contralateral carotid artery and in six further cases via other collateral vessels. In the extracranial area, an internalisation of the flow pattern of the superficial temporal artery was found if the bloodstream from the anastomosis passed through the MCA. Similar changes at the external carotid artery were mainly due to the changed haemodynamics resulting from the extracranial occlusion of the internal carotid artery. No correlation was found between the clinical neurological course and haemodynamic data. The only indication for the EC-IC bypass, as we see it at the moment, is prophylactic surgery, such as, for example, treatment of giant aneurysms and definitely insufficient crossflow. All other indications that have been suggested after the publication of the results of the EC-IC Bypass Study Group will have to be confirmed by further study.