Prognostic Importance of Blood Rheology in Acute Stroke

Increased blood viscosity has been described in patients with acute stroke, associated with elevations of hematocrit and/or plasma fibrinogen concentration [3, 13, 14]. Increased red cell aggregation [8, 11] and decreased blood filterability have also been reported [8, 10, 14, 17]. These rheological abnormalities may promote cerebral ischemia in areas of low blood flow. In patients with cerebral ischemia, hematocrit, fibrinogen, and yield stress showed inverse correlations with cerebral blood flow [6]. Conversely, pilot studies of hemodilution [5, 20] and defibrination [7] have shown encouraging results in treatment of acute cerebral infarction. White cell capillary plugging may also play a role in cerebral ischemia [24], and this may be promoted by the increased white cell count in acute stroke [11].