[Ambulatory measurement of arterial pressure]

Ambulatory measurement of the blood pressure may be considered as a reliable technique. Its validity is demonstrated by two types of factors: the first is physiological: the nycthemeral curves obtained with this method are similar to those provided by the first invasive studies, and especially show a definite nocturnal depression in most individuals; the second is epidemiological: the ambulatory blood pressure level is closely correlated with the left ventricular mass, measured on sonograms and has a good predictive value of future cardiovascular accidents. Its superiority over the standard measurement method, lies in the very principle of the method. It is an automatic measurement: the "white coat" artefact is therefore avoided. It is a repetitive and prolonged measurement, permitting therefore to analyze a complete nyctohemeral cycle instead of a single sample. Finally, it is an ambulatory measurement: the patients is therefore in his usual environment and not in the peculiar context of a medical office. However, the limitations of the method must be presented. The most important result from the interpretation of the collected data: the so-called aberrant values are identified from very arbitrary criteria and their elimination may be at the origin of errors; the currently available "norms" are only a indication and do not enable the physician to decide decisively between abstention and therapeutic intervention. An ambulatory blood pressure recording is particularly justified in the following two circumstances: 1) definite dissociation between elevated blood pressure at the consultation and moderate visceral repercussions; 2) hypertension resisting to an apparently well managed treatment that one hesitates to increase.