Elevated erythrocyte (RBC) aggregation (RBC-A) may contribute to the p
athogenesis of stroke and stroke recurrence. We measured RBC-A at low
shear in 55 patients with acute ischemic stroke and in 24 age-balanced
controls without cerebrovascular disease or vascular risk factors. RB
C-A was significantly elevated in subgroups of stroke patients who wer
e hypertensive, diabetic, or both, compared with either stroke patient
s lacking these risk factors (p at least <0.01) or healthy elderly (al
l p < 0.001). RBC-A was normal in stroke patients (n = 14) free of bot
h diabetes and hypertension. In a multivariate linear regression model
glycosylated hemoglobin (p < 0.0001), plasma viscosity (p < 0.006) an
d systolic blood pressure (p < 0.05) were each independently significa
nt and together accounted for about 52% of the variation in RBC-A in a
cute stroke patients. No relationship was detected between RBC-A and i
nfarct size or among the major subtypes of ischemic stroke. The result
s suggest that vigorous control of both blood glucose and blood pressu
re may reduce the potentially damaging effects of elevated RBC-A in th
e cerebral vasculature.