The relationship between endothelial dysfunction and 24-hour blood pressure rhythm in patients with arterial hypertension.

The purpose of the study was an investigation of relationships between duration of arterial hypertension (AH), 24-hour blood pressure (BP) rhythm and endothelial function. 18 (mean age 50+/-8.7; 8%-male, 10%-female) outpatients with AH were included in the study. All subjects underwent off-therapy 24-hour ambulatory BP monitoring and vascular Doppler echography of the brachial artery. Hypercholesterolemic subjects, diabetics, smokers and patients with Raynaud's phenomenon were excluded from the study. Compared with dipper women, non-dipper women showed statistically significant lowering of FMD (11.8+/-4.2% vs. 3.4+/-3.85%, p<0.005). The same fact was observed in men (16.5+/-3.45% dipper vs. 4.0+/-1.08% non-dipper, p<0.05). Association of the duration of arterial hypertension with FMD was significant (7.9+/-4% (<10 y) vs. 2.0+/-3% (>10 y); p= 0.017). Compared with dipper patients, non-dipper subjects showed an impaired endothelial function (11.4+/-2% vs. 3.5+/-2.6%; p=0.0006). The present data confirm the presence of disturbed endothelium-dependent vasodilatation in arterial hypertension. The study showed significant relation between duration of arterial hypertension and FMD. Furthermore, these results demonstrate that the main factor, which leads to endothelial dysfunction, is the shortage in the lowering BP during the night.