Cerebral artery blood flow in relation to age and menopausal status

Objective: To investigate vascular reactivity in women's cerebral arteries from reproductive age to postmenopause. Methods: The pulsatility index (PI) was measured cross-sectionally in the internal carotid and middle cerebral arteries of 120 women, using a Doppler ultrasound system. Fifteen women were enrolled in each of eight 5-year intervals, spanning ages 20-59 years. Results: In the population as a whole, there was a slight but statistically significant correlation between age and the PI in both arteries, but not after excluding postmenopausal subjects. A significant correlation was found between PI and months since menopause (but not chronologic age) in the postmenopausal women, There was also a statistically significant difference in the PI values for both arteries between pre- and postmenopausal women of similar age. Conclusion: Menopause causes a significant increase in the PI of women's cerebral arteries. In postmenopausal women, there is a significant correlation between the PI of the internal carotid and middle cerebral arteries and menopausal but not chronologic age. This effect may be one of the mechanisms by which menopause is associated with the known higher risk for coronary heart disease observed in women.