Incidence of symptomatic vertebrobasilar stenosis in the general population.

Sir, In their interesting paper on the incidence of symptomatic vertebrobasilar stenosis in the general population, Marquardt et al. (2009) report the results of magnetic resonance angiography (MRA) studies of 141 patients with prior minor vertebrobasilar events, having detected 550% stenosis in 26.2% of cases. They also describe the results of carotid ultrasound studies performed on 357 patients who had suffered carotid transient ischaemic attack or minor stroke, with 11.5% of cases presenting 550% stenosis of the vessel responsible. They conclude that the prevalence of 550% symptomatic vertebrobasilar stenosis is