Evaluation of nocturnal blood pressure by the Multi-P Analysis of 24-hour ambulatory monitoring.

Ambulatory blood pressure monitoring (ABPM) is utilized to identify "dippers" and "non dippers" among hypertensives. Such a classification has either prognostic or therapeutical implications. Rigid definitions of nocturnal time period (e.g., from 10 p.m. to 7 a.m.) may not correspond to actual sleep patterns, and thus may lead to faulty interpretations. In our study, we analyzed 32 ABPM; diurnal and nocturnal blood pressure (BP) were assessed by three different ways: the patients' diary method; fixed intervals utilized by Spacelabs software; Multi-P Analysis (MPA) of the data. MPA method proved to be effective to evaluate nocturnal BP values. In comparison with Spacelabs program, it seems to define more precisely nocturnal BP, which differs less from the real sleep-time values. This modifies the percentage of dippers, which is greater than that obtained by Spacelabs program and equal to that calculated by the patients reported nocturnal sleep intervals. These results suggest that MPA method may be a contribution to a better definition of nocturnal BP.