Increased erythrocyte adhesiveness and aggregation in peripheral venous blood of women with pregnancy-induced hypertension

OBJECTIVE: To study the state of erythrocyte adhesiveness/aggregation in the peripheral blood of women with pregnancy-induced hypertension as well as in matched controls using a simple slide test and image analysis. METHODS: We recruited 25 women with pregnancy-induced hypertension. Twenty-five age- and gestational age-matched normotensive volunteers took part in the study and served as controls. Blood smears were evaluated by an image analysis system (INFLAMET). Quantitative measures of erythrocyte aggregation were used to describe the state of erythrocyte adhesiveness/aggregation such as vacuum radius, which measures the spaces between the aggregated erythrocytes. The number of participants was established by power analysis (given alpha of 0.05 and 80% power and considering a minimum difference to detect 4 microm in vacuum radius with a standard deviation of approximately 5). RESULTS: A significant (P =.002) increment in the state of erythrocyte aggregation was noted in the study group compared with the controls, the vacuum radius values being 16.1 +/- 1.3 and 10.3 +/- 1.2, respectively. Erythrocyte sedimentation rate but not fibrinogen concentration was significantly elevated in the study group. The increased aggregation correlated significantly with fibrinogen concentration, systolic, and diastolic blood pressures. CONCLUSION: We observed increased aggregability of red blood cells in hypertensive conditions of pregnancy. Our findings are significant in that they reveal blood pressure-related increment in red cell adhesiveness/aggregation despite there being no significant increment in clottable fibrinogen concentrations.