[Circadian rhythm of blood pressure: non-dipping pattern and cardiovascular risk]

24h ambulatory blood pressure monitoring (ABPM) can easily detect the circadian blood pressure (BP) pattern: usually, systolic and diastolic blood pressure (BP) show a nocturnal fall. Nocturnal BP values do not however always decline in essential hypertension: the subjects who show a nocturnal BP fall of at least 10% are called dippers; in other subjects, called non-dippers, BP behaviour is characterized by a lack of or very limited nocturnal BP fall. Several studies have investigated the relationship between the lack of or reduction of nocturnal BP fall (non-dipping pattern) and cardiovascular risk, showing not only an increase of target-organ damage (heart, brain, kidney), but a greater frequency of cardiovascular events (stroke, myocardial infarction, etc.) also and higher cardiovascular mortality in non-dippers subjects, both hypertensives and normotensives. Therefore, a non-dipping pattern may be an additional risk factor. Thus, ABPM could be a useful method to evaluate the initial global cardiovascular risk in patients with hypertension, and an adequate antihypertensive therapy should aim not only at lowering high BP values, but also at re-establishing the physiological nocturnal BP fall.