BLOOD-PRESSURE VARIABILITY - CLINICAL AND THERAPEUTIC IMPLICATIONS

The high degree of the intra-individual variability of blood pressure (BP) is related both to biological and technological factors: the biol ogical components of variability are either linked to sympathetic syst em and respiratory movements or induced by physical and psycho-sensori al stresses; the technological sources of variability are the apparatu s and the doctor. The consequences of this high variability can be qua ntified: the risk for a between-visit change of 35 mmHg for systolic B P (and 17 mmHg for diastolic BP) to be due to the spontaneous BP varia bility, is as high as 95%. Moreover, according to the regression to th e mean, in selected patients with a mean SBP as high as 160 mmHg, a me an spontaneous decrease of 9 mmHg is expected to occur, at the next vi sit. The physician has then to manage the lack of accuracy of clinic B P measurements. For this purpose, three strategies have to be used: th oroughly examining the patient (if associated with an organ damage, th e high BP undoubtedly requires to be treated); rigorously taking into account the published recommendations of BP measurements (the sources of error are now wellknown and may be easily corrected); finally, usin g the most sophisticated methods of BP measurements (elf BP measuremen t), semi-ambulatory or ambulatory BP monitoring, exercise testing), wh ich in some circumstances, may provide useful additional information.