[Spontaneous clinical course of asymptomatic vascular processes of the extracranial cerebral arteries. Further results of a long-term prospective study].

The natural history of a prospectively selected group of neurologically asymptomatic patients with extracranial arterial disease (EAD) was studied. 35 of 184 patients died over a period of follow-up of four years (mean = 21 months). Only four of them had a stroke, while coronary artery disease was the far more common cause of death (n = 19). Among those patients still alive 12 reported transient ischaemic attacks, two a stroke, and 116 remained asymptomatic--only two patients could not be followed. Thus by life-table analysis, the cumulative stroke rate was only 6%, irrespective of death or survival, about the same as the average risk of death in a normal population (5%). However, the probability of EAD progression was 88% as revealed by subsequent continuous-wave Doppler analysis of both the carotid and vertebral arteries in the neck. Neither the degree of initial EAD nor its progression during follow-up were found to represent significant indicators of the patient's cerebrovascular risk. Since the majority of symptomatic patients did not proceed to frank strokes but presented with TIAs, prophylactic surgical treatment may reasonably be delayed.