Disappearing obstructions in extracranial cerebral arteries.

Between 1973 and 1978 spontaneous lysis of obstructions in an external cerebral artery was detected in seven out of 3500 patients who suffered from symptoms of cerebrovascular failure in the territory of the internal carotid or vertebral artery. All patients underwent our routine cerebrovascular Doppler ultrasound examination. In the seven patients a high grade obstruction in the internal carotid artery (six cases) or in the brachiocephalic trunk (one case) was found by Doppler and/or angiography 1-3 days after the onset of the symptoms. On a second examination 4-30 days later these obstructions were no longer present either in the Doppler examination and on the angiograms, or in the surgically exposed vessel. These findings suggest that spontaneous lysis of the obstructions must have occurred. Furthermore vascular surgery should not be delayed more than 3-7 days without another reliable vascular examination.