Hemoglobin concentration and prognosis in symptomatic obstructive cerebrovascular disease.

A total of 1,377 patients with symptomatic obstructive cerebrovascular disease (most commonly, internal carotid artery occlusion) entered a trial in which they were randomized to either medical or surgical (extracranial-intracranial bypass) therapy. All but 8 had hemoglobin estimations performed at entry. The patients were followed for an average of 55.8 months. In the medical group, the 325 patients with high normal hemoglobin concentration (15 g/l or more) suffered no more ischemic strokes than the 382 patients with lower values (less than 15 g/l). Those strokes that did occur were no more severe in the high than the low hemoglobin group. Hemoglobin concentration did not emerge as a prognostic factor in those patients treated surgically (n = 662). This prospective study counters the hypothesis that high normal hemoglobin concentration is associated with poor outcome in patients with symptomatic obstructive disease of the carotid and cerebral arteries.