Clinical value of blood pressure variability.

Blood pressure (BP) is known to continuously fluctuate over time and both the amplitude and frequency of these changes have been reported to be clinically relevant. Indeed, it has been shown that the occurrence of pronounced BP changes at the time of the physician's visit may introduce errors in the diagnosis of hypertension and in the assessment of the efficacy of antihypertensive treatment. Moreover, several studies have provided evidence that the end organ damage of hypertension is not only more closely related to 24h average BP values than to casual BP readings, it is also significantly and independently related to the degree of BP variability during the day and night. Results from a recent follow-up study support the possibility that the degree of BP variability may also have prognostic relevance in hypertensive patients. Recent progress in technology has offered us non-invasive techniques for the assessment of beat-to-beat finger blood pressure variability and for the detailed quantification of all its frequency components from the fastest to the slowest ones. Their role as additional surrogate endpoints in essential hypertension needs to be addressed in future studies.