Nocturnal Blood Pressure Versus Nondipping Pattern

Abstract

Thirty years ago methods to assess blood pressure (BP) automatically during regular living conditions represented a new dawn in the field of hypertension. Today ambulatory blood pressure monitoring (ABPM) is a tool available not only in specialized clinics but also in many segments of primary care. A large number of studies have demonstrated the better reproducibility and the prognostic superiority of BP values obtained by using ABPM as compared with the BP obtained from standard clinical measurements. The prognostic value of ambulatory BP was established for the general population as well as for hypertension in general or under specific conditions such as refractory hypertension, diabetes, chronic renal insufficiency, or pregnancy.1 Based on outcome and on epidemiological studies, reference values for ambulatory BP have been recommended even though limitations about their precision still exist today.2 Because ABPM provides large numbers of measurements, researchers have been tempted to look for more information than just the average of BP values during 24 hours or over more restricted periods such as the day, night, or morning. Therefore, assessment of other BP parameters has been considered. Blood pressure changes during the 24-hour period, the so-called circadian variability,3 and BP variation among measurements, intrinsic variability,4 have received increasing attention. Although the significance of intrinsic variability has been challenged when BP is measured intermittently every 15 or 20 minutes, circadian variability has become an increasingly used parameter even though reproducibility has introduced some limitations. Clinical observations have identified subjects with a blunted decline in the physiological BP nocturnal fall, the nondipper pattern.5 …