AGE AND SEX-DIFFERENCES IN CEREBRAL HEMODYNAMICS - A TRANSCRANIAL DOPPLER STUDY

Background and Purpose-Hemodynamic factors seem to play an important r ole in the pathogenesis of cerebral ischemic events. The aim of this s tudy was to evaluate whether changes in cerebrovascular reactivity occ ur in women after menopause. Methods-Using transcranial Doppler ultras onography, we studied the changes of flow velocity after hypercapnia i n the middle cerebral arteries of 45 healthy premenopausal women (mean age, 32.3 years; range, 20 to 47 years) and 40 postmenopausal women ( mean age, 54.4 years; range, 48 to 64 years). The same measurements we re recorded in two groups of healthy male subjects age matched with pr emenopausal (45 subjects) and postmenopausal women (40 subjects). More over, a subgroup of postmenopausal women aged 48 to 53 years (15 subje cts) were compared with a group of 15 premenopausal women of the same age, We obtained hypercapnia with breath holding and evaluated cerebro vascular reactivity with the breath-holding index (BHI). Results-BHI w as significantly lower in postmenopausal women (0.89+/-0.3) than in pr emenopausal women (1.59+/-0.3; P<0.0001) and in young (1.34+/-0.5; P<0 .001) and old men (1.20+/-0.4; P<0.04). In the latter group, BHI was s ignificantly lower than in premenopausal women (P<.0001). BHI values w ere also significantly lower in postmenopausal than in premenopausal w omen of the same age (0.81+/-0.1 versus 1.34+/-0.1; P<0.0001), Conclus ions-These findings suggest that the large reduction of cerebrovascula r reactivity in postmenopausal women cannot be considered a simple fac tor related to aging but is probably influenced by hormonal changes. T he alteration in cerebrovascular regulation could be involved in the i ncrease of cerebrovascular disease in postmenopausal women.