[Doctor's-office blood pressure, home blood pressure, ergometry blood pressure and 24-hour blood pressure. The correlations with the echocardiographic parameters of heart muscle mass]

24-hour blood pressure measurement in antihypertensive drug trials: data requirements and methods of analysis

Non-invasive ambulatory blood pressure monitoring is an appropriate technique for the identification of the target population requiring antihypertensive treatment, since the systematic bias seen in casual clinic measurement is removed. The use of the technique in controlled clinical trials leads to a reduction in the sample size required to show a treatment difference in antihypertensive effect compared to sporadic single measurements, although in practice the number of recruited patients can considerably exceed the number of evaluable patients, due to poor compliance or incompleteness of data. In addition, the equality of observation essential in clinical trials cannot be controlled to the same degree as is possible with clinic measurements. Comparison of estimators of the overall characteristic blood pressure reveals that the 24-hour mean value produces an adequate estimator. A description of the individual blood pressure profile is obtained using smoothing procedures, the moving interval average providing a robust and simple approach. Clinically meaningful characteristics of the profile are difficult to define due to a dearth of information on prognostic importance of the features of the 24-hour blood pressure profile. Smoothed individual profiles can be combined to produce graphical descriptive treatment group summaries.

[The significance of 24-hour blood pressure monitoring in the diagnosis and therapy of arterial hypertension]

The use of ABPM allows an improved assessment of blood pressure (BP) and therefore of the individual cardiovascular risk. It is able to identify patients who truly need therapy more exactly. Mostly patients with white coat hypertension who don't need therapy are identified. Furthermore, ABPM correlates more closely to target organ damage and to cardiovascular morbidity and mortality. This may be helpful to treat especially those patients who truly need therapy. BP exhibits a typical circadian rhythm with the highest values during the early morning hours and a decline during the night. A change of the day/night rhythm during shift work leads to an adaptation of BP rhythm. The early morning rise of BP and heart rate is accompanied by hemodynamic, rheological and biochemical alterations, which together may contribute to the increased frequency of vascular complications during the morning hours. The nightly decline of BP is often absent in patients with secondary hypertension and cardiac or renal organ damage. A lack of the nocturnal BP decline should therefore lead to further patients' evaluation. Elevated nocturnal BP seems to worsen the prognosis. ABPM offers better individual control of BP in patients on treatment and therefore is helpful to optimize the treatment. A more exact individual BP control during the awakening and sleeping period is possible as well as an avoidance of overtreatment. Patients could be protected both from prescription of too many drugs and from lowering BP too much. A further advantage lies in an improved control of patients with nocturnal hypertension.