Microvascular endothelial function is blunted in postmenopausal females with frequent hot flushes

Hot flushes of menopause are associated with elevated blood pressure (BP) and diminished macrovascular endothelial function, an initiating factor in the onset of atherosclerosis. Whether microvascular endothelial function is impaired in females with hot flushes, however, remains unknown. We hypothesised that postmenopausal females with hot flushes would have reduced microvascular endothelial function and elevated BP in comparison to age-matched females without hot flushes. Participants were healthy postmenopausal females, aged 45-70 years; participants experiencing at least three hot flushes per day were placed in the hot flush (HF) group (n = 16), whereas participants with no history of hot flushes were placed in the non-HF group (n = 18). Heart rate (ECG) and BP (finger plethysmography) were measured during a 10 min rest period, and endothelial function was measured with pulse amplitude tonometry (EndoPAT 2000), quantified by the reactive hyperaemia index (RHI) and the natural logarithm of the RHI (LnRHI). Groups were similar in age, age at menopause and body mass index, in addition to systolic BP, diastolic BP and heart rate between groups (P > 0.05). The RHI was lower in the HF group (1.87 ± 0.47 a.u.) compared with the non-HF group (2.31 ± 0.67 a.u., P = 0.047), and the difference between LnRHI in the HF group (0.63 ± 0.21 a.u.) and the non-HF group was nearly significant (0.80 ± 0.27 a.u., P = 0.052). New findings from this study demonstrate a lower microvascular endothelial function in females with hot flushes in comparison to females without hot flushes, although BP and heart rate were not different between the groups. The reduced microvascular endothelial function demonstrated in females with hot flushes is likely to contribute to greater cardiovascular disease development.