Relationship between short-term and long-term blood pressure variabilities in essential hypertensives

This study was designed to analyse the relationship between the different blood pressure (BP) variabilities obtained in a non-invasive way and to determine the potential contribution of aging, severity of hypertension and increased ventricular mass to these different BP variabilities. Two hundred and six hypertensive patients underwent a 24-h ambulatory BP measurement (ABPM) as well as a photoplethysmographic BP recording and a standard echocardiography. Nocturnal BP fall and standard deviations of hourly mean BP levels as well as post-prandial fall in BP were calculated from the 24-h ABPM and were considered as indexes of long-term variability. Baroreflex sensitivity (BRS) and spectral powers of systolic BP, diastolic BP and heart rate (HR) over the low frequency band (LF: 0.05--0.14 Hz) were obtained from photoplethysmographic recording and were used as indexes of short-term variability. Short-term variability indexes were shown to be significantly related to those of long-term variability. A decrease in LF spectral powers was associated with a particular profile characterised by an attenuation of nocturnal BP fall, an increase of daytime BP standard deviations, an increase in post-prandial BP fall, a decrease in BRS and to a lesser extent, a diminution in night-time HR standard deviation. Moreover, a negative significant relationship was found between standard deviation of daytime systolic BP and both night systolic BP fall and BRS. Age and nocturnal BP level were associated with all BP variability disorders, whereas left ventricular hypertrophy was associated only with a decrease in LF spectral powers and in night BP fall, and an increase in standard deviation of daytime BP. Finally, LF spectral power of SBP was identified as independently predicted by age and night SBP fall. Journal of Human Hypertension (2001) 15, 41-48