Arterial applanation tonometry: technical aspects relevant for its daily clinical use.

S everal clinical epidemiological studies have suggested the relevance of the assessment of central blood pressure by means of noninvasive methods for a better evaluation of cardiovascular risk [1–3]. In particular, attention has been focused on the phenomenon of pulse pressure amplification in the clinical evaluation of cardiovascular patients [4–6]. Applanation tonometry is currently considered the reference method for noninvasive evaluation of central blood pressure and central pulse wave analysis [7,8]. Even if transcutaneous arterial tonometry is not yet considered to be one of the diagnostic tests recommended for routine arterial hypertension management, all the same, it represents a useful tool for more in-depth investigation of vascular changes in a number of clinical conditions characterizing daily practice. In particular, it is useful in conditions in which an accurate central pulse wave analysis is required, for an indirect estimate of myocardial function or cardiac work. Therefore, it is necessary that central blood pressure values recorded with this method are reliable and that parameters describing central arterial pressure waveform faithfully reflect the corresponding ones invasively recorded in the ascending aorta. The study by Hirata et al. [9], published in this issue of the Journal of Hypertension, focuses on a particular aspect concerning the position of the patient during acquisition of the central arterial pressure waveform, which appears to be an important requirement to optimize standardization of applanation tonometry in clinical practice. As a matter of fact, some tonometric devices are used with the patient in sitting position, whereas other instruments require the patient to lie down in a supine position during arterial pressure waveform recording.