[Effect of hormone replacement therapy on hemorheology in postmenopausal women]

Our study is to observe the effects of conjugated equine estrogen (CEE) combined with medroxyprogesterone acetate (MPA) on hemorheology in postmenopausal women in order to evaluate mechanism responsible for the increase in the incidence of cardiovascular disease after menopause and also to provide proper instruction and advice of hormone replacement therapy (HRT) for postmenopausal women.

60 healthy postmenopausal women were assigned to 3 groups randomly, 20 cases in each group. Group A: CEE 0.625 mg/d + MPA 2 mg/d + calcium carbonate co. (Ca-D) 600 mg/d. Group B: CEE 0.3 mg/d + MPA 2 mg/d + Ca-D 600 mg/d. Group C: Ca-D 600 mg/d only served as control. Measurements of hemorheological parameters were performed before and 6 months after treatment.

After 6 months of HRT, group A: blood viscosity under the shear rate of 94.5 s-1 dropped from (5.23 +/- 0.37) mPa.s to (5.03 +/- 0.43) mPa.s (P < 0.05), plasma viscosity dropped from (1.66 +/- 0.19) mPa.s to (1.58 +/- 0.15) mPa.s (P < 0.05), erythrocyte deformability dropped from (4.76 +/- 0.32) mPa.s to (4.54 +/- 0.34) mPa.s (P < 0.05). Group B: blood viscosity under the shear rate of 94.5 s-1 dropped from (5.10 +/- 0.30) mPa.s to (4.87 +/- 0.30) mPa.s (P < 0.05), erythrocyte deformability dropped from (4.65 +/- 0.34) mPa.s to (4.43 +/- 0.29) mPa.s (P < 0.05). No change was found in the control group. After treatment, the levels of plasma viscosity and fibrinogen in group A were much lower than that in group C (P < 0.05). The whole blood viscosity and plasma viscosity in group B were much lower than that in group C (P < 0.05). Thrombelastogram study demonstrated no change regardless HRT or not (P > 0.05).

Both different dosages of CEE have favor effects on blood viscosity and erythrocyte deformabillity, which could play the role in preventing cardiovascular disease in postmenopausal women.