Association of hemorheological parameters and risk of stroke in hypertensives of Indian origin

The blood viscosity parameters of one hundred and fifty cases of WHO grade I and II hypertension of Indian origin, on treatment with calcium antagonis ts, were measured and a six-monthly follow up was conducted for a period of three years. The whole blood viscosity (WBV), plasma viscosity (PV), red c ell rigidity (RG) and hematocrit (Hct) were monitored. Occurrence of stroke was considered as the outcome variable and it was observed that sixteen ca ses of stroke occurred during the follow up period (10.7% incidence). After excluding known risk factors of age, sex, addictions, blood pressure level s, cholesterol levels and underlying diseases, it was observed that an incr eased whole blood viscosity > 6 centiPoise was associated with an increased risk of stroke (Relative risk 2.9, 95% confidence interval 2.2 to 3.7). An increased red cell rigidity in a hypertensive patient was found to be an i ndependent risk factor for stroke. Patients with red cell rigidity greater than 4 had 4 times (Relative risk 3.6, 95% confidence interval 3.2 to 4) hi gher risk of stroke as compared with patients with red cell rigidity levels less than 4. Treatment with drugs modifying the rheological profile and ai ming at improving the red cell deformability should thus be considered in h ypertensive patients in an attempt to prevent the occurrence of stroke.