Blood pressure variability. Importance in research and in clinical hypertension.

mean value, but also 24h blood pressure variability seems to be independently related to the end organ damage of hypertension. This is illustrated in figure 1, which is taken from a study where 108 hypertensive patients underwent a 24h intra-arterial blood pressure monitoring in ambulatory conditions by Oxford technique 16. A score based on clinical and laboratory examinations was used to quantify the severity and the rate of end organ damage related to hypertension. The 108 patients were subdivided into five groups with progressively higher 24h mean blood pressure levels. In each group, the hypertensive patients with greater blood pressure variability (evaluated as the standard deviation of the 24h mean blood pressure) showed more severe and more frequent end organ damage than the patients with similar 24h mean values but less pronounced 24h blood pressure variability.