[Hyperviscosity. An independent risk factor after a survived stroke]

Several lines of evidence indicate that pathologic blood flow properties lead to a deterioration in the prognosis of patients with arteriosclerotic diseases, especially after a stroke. We tested this hypothesis in a prospective study including 625 patients with a first stroke that dated back less than five years (7.4 +/- 11.3 months, mean +/- sd). Investigated parameters were native and hematocrit standardized blood viscosity (at shear rates 0.7 s-1, 2.4 s-1 and 95.5 s-1) and its most important determinants (i.e. hematocrit, plasma viscosity, fibrinogen), erythrocyte sedimentation rate, leukocytes, cholesterol, triglycerides, blood pressure and BMI. For smoking patients were scored into four groups. Two years after these investigations a follow up was performed (response rate 96.3%). 71 patients with study endpoint (second stroke, heart attack or death due to the underlying cardiovascular disease) were identified. In 65 cases matching of a patient with and a patient without endpoint was possible. Criteria for matching were: cholesterol, triglycerides, diabetes, BMI, gender, age blood pressure, smoking, time interval between first stroke and rheologic measurements and concomitant diseases. Native blood viscosity was significantly higher in patients with endpoint (p less than 0.01) as compared to patients without (37.4 +/- 12.5 mPas vs 32.1 +/- 8.9 mPas at a shear rate of 0.7 s-1). All other variables did not differ significantly between both groups. It is concluded that in patients, who have survived a first stroke, high blood viscosity is a risk factor, independent from the accepted ones.