Indirect measurement of blood pressure and its clinical significance - Blood pressure measurement at random, selfmeasurement of blood pressure, measurement of blood pressure during and after standardized ergometry, 24-hour-measurement of blood pressure.

Since the cuff sphygmomanometer has been introduced by Riva-Rocci in 1896, indirect measurement of blood pressure has attained its high present standard by dint of amendments and improvements. 20 - 30% of patients with mild arterial hypertension, based on the measurement of blood pressure at random, are normotensive according to the criteria of ambulant 24-hour-measurement of blood pressure (AMBP), i.e. they have a ''doctor's white coat'' hypertension. Besides the AMBP, self-measurement of blood pressure and standardized ergometry are able to detect patients with a situational increase of blood pressure. On the other hand, AMBP is best able to detect even the early stage of essential arterial hypertension with mainly functional elevation of the peripheral vascular resistance. This method is also the most suitable for prognostic appraisal, especially because it reveals the nocturnal blood pressure characteristics. If there is no physiological fall of blood pressure at night (non-dipper), left ventricular hypertrophy is found to be more frequent and more pronounced in echocardiography. The cardiovasular morbidity and lethality of these non-dippers is very much higher than in hypertension patients with normal diurnal blood pressure profile (dipper), although these dippers also have a poorer prognosis compared to normotensive subjects. It remains to be stated: Measurement of blood pressure at random is the basic or minimal method with the broadest application. Self-measurement of blood pressure provides an optimized basis for appraisal in establishing the indication for antihypertensive therapy and monitoring treatment. Standardized ergometry and AMBP are complementary methods for optimal individual treatment of hypertensive patients. Blood pressure measurements at random, measurement under exercise, and self-measurement of blood pressure must always be carried out at a constant time interval from the last intake of tablets in order to enable standardized monitoring of treatment. Today, the trough to peak ratio plays a major role in appraising the duration of action of an antihypertensive when administered in a single dose (the minimum effect 24 hours after taking the tablets should be at least 50% in relation to the maximum effect!). Measuring blood pressure at random the placebo-corrected trough to peak ratio is now higher (especially in the untreated phase) owing to the ''doctor's while coat'' effect than when determined from the corresponding AMBP values. AMBP is hence the better method in this context and thus guarantees greater security of treatment. Ar present, the best and most comprehensive method for confirming the diagnosis, establishing the indication for pharmacotherapy and monitoring of treatment in arterial hypertension, therefore, is AMBP, especially since it also reveals the nocturnal blood pressure characteristics. At the same time it provides the clinically most important information in order to attain a largely normal prognosis of our hypertension patients.