Variability of direct arterial blood pressure in essential hypertension--relationships between the fall of blood pressure during sleep and awake resting hemodynamic parameters.

The relationship of continuous ambulatory intra-arterial blood pressure over a 24-hour period and awake resting hemodynamic parameters measured by echocardiography was studied in 21 patients with essential hypertension (WHO stage I & II): Left ventricular wall thickness at end-diastole correlated strongly with average SBP and weakly with average DBP during both waking and sleeping periods. Variability of blood pressure taken during waking and sleeping periods was not significantly correlated with any hemodynamic parameters measured by echocardiography. Variability of SBP during sleep had a significant correlation with age; however the fall of blood pressure during sleep had no significant correlation with age. Fall of blood pressure during sleep was significantly correlated to resting awake TPR. In patients with essential hypertension, the above results demonstrate that subjects with thicker left ventricular wall have higher average continuous blood pressure over 24-hours and suggest that there is a tendency for greater falls in blood pressure during sleep to occur in subjects with higher TPR and that older subjects have greater variabilities of SBP during sleep.