Relationship of 24-hour blood pressure rhythm with endothelial function and blood rheology

The purpose of the study was to investigate relationships between sex, blood pressure level, duration of arterial hypertension (AH), 24-hour blood pressure (BP) rhythm, endothelial function (EF) and blood rheological parameters. 23 (mean age 50+/-8.73) outpatients with AH were included in the study. All subjects underwent off-therapy 24-hour ambulatory BP monitoring, investigation of blood rheological parameters and high resolution vascular dopplerography Dipper patients showed lower rate of platelet aggregation and platelet adhesion, than it was in non-dippers (86.42+/-8.20 vs. 99.36+/-5.93; P=0.0018 and 24.2+/-11.54 vs. 42.16+/-13.71; P=0.01). Viscosity was higher in patients with endothelial dysfunction, than it was in patients without it (0.064+/-0.01 vs. 0.051+/-0.0035; P=0.004). Compared with dippers, non-dippers showed an impaired EF (11.4+/-2% vs. 3.5+/-2.6%; p= 0.0006). The present data suggest the presence of disturbed endothelium-dependent vasodilatation and alterations in rheological indices in AH. According to the results obtained, the main factor, which leads to endothelial dysfunction and increase in platelet aggregative and adhesive activity, is the shortage in the lowering BP during the night. Consequently, hypertensive patients with non-dipper circadian blood pressure profile have to be assessed as a high risk group for development of future cardiovascular and cerebrovascular complications.