Consensus document on non-invasive ambulatory blood pressure monitoring

During a conference devoted to problems of non-invasive ambulatory blood pressure monitoring held in Berlin on March 2 and 3 1990, the following issues were intensively discussed and a consensus was reached on certain aspects. A number of devices are now available which may be considered acceptable in terms of accuracy and reliability, patient acceptability, computer compatibility and cost. To standardize data analysis, day and night blood pressure profiles should be analysed, the daytime period running for 15 ± 2 h (7.00 a.m. to 10.00 p.m.) and the night-time for 9 ± 2 h (10.00 p.m. to 7.00 a.m.). Data analysis should provide mean and median systolic, diastolic and mean arterial pressures and heart rates for the daytime, the night-time and the full 24-h period. The results of a meta-analysis of studies on non-invasive ambulatory blood pressure monitoring in healthy and apparently normotensive subjects suggest that a daytime mean blood pressure of ≥ 135/85 mmHg may represent a hypertensive condition (the full 24-h mean may be lower). This may be taken as the provisional cutoff level between a normal and a high daytime blood pressure, pending the results of studies from non-selected general populations including untreated hypertensives. Ambulatory blood pressure monitoring appears to be a better predictor of left ventricular hypertrophy than causal blood pressure measurements are. Since increased left ventricular mass is a strong predictor of an adverse prognosis, ambulatory monitoring may also be more predictive of prognosis than casual readings. Non-invasive ambulatory blood pressure monitoring has proved to be an excellent way of detecting so-called white-coat hypertension, which is present in about 20% of subjects with elevated office blood pressures. In these subjects, it may help to avoid unnecessary drug treatment. In addition, ambulatory blood pressure monitoring is a particularly important technique for clinical trials on the antihypertensive effect of single drugs or combined drug regimens. It has been shown that 24-h mean blood pressure is more reproducible than conventional blood pressure values, so that the number of patients required for antihypertensive drug trials may be considerably reduced.