8.4 DIURNAL CHANGES IN CENTRAL PRESSURE AND PULSE WAVE PARAMETERS IN HEALTHY SUBJECTS

Abstract

Purpose: The feasibility of pulse wave analysis (PWA) over 24 hours with oscillometric devices has already been shown and first studies indicate additional information compared to single measurements. Nevertheless, diurnal patterns of PWA parameters in healthy subjects, which can potentially serve as a reference, are currently missing. Therefore, the aim of this study was to perform 24h-PWA measurements in healthy subjects over a wide age range and to analyse day/night differences. Methods: 91 well defined healthy subjects underwent 24h PWA measurements using the Mobil-O-Graph device (IEM, Germany). The subjects were categorized in three age groups (20–29 years, 30–49 years, 50–69 years). Daytime (9–21h) and nighttime (0–6h) averages were calculated. Results: A significant dipping behaviour in all age groups could be found for diastolic blood pressure (> 14 mmHg in all age groups, p<0.05), peripheral systolic blood pressure (> 15 mmHg, p<0.05) and central systolic blood pressure (> 9 mmHg, p<0.05). A significant rising effect in all age groups was found for the reflection magnitude (> 8 %). In contrast, the day/night difference in augmentation index was age dependent and this dependency remained also for AIx75, see table. Conclusions: Prominent pressure dipping and a rise in reflection magnitude were present in all age groups during nighttime, while diurnal changes in augmentation index showed an age-dependency. This differing behaviour of PWA parameters should be investigated in further studies. Furthermore, the observed effects of diurnal changes in healthy subjects may provide a basis for reference profiles for future patient evaluation. 20–29 years 30–49 years 50–69 years Day Night Day Night Day Night pSBP (mmHg) 118.8 * 103.4 124.8 * 109.0 123.0 * 105.8 pDBP (mmHg) 75.7 * 59.5 81.4 * 64.2 79.6 * 64.8 cSBP (mmHg) 106.3 * 97.1 114.8 * 103.3 114.5 * 100.7 cDBP (mmHg) 77.4 * 60.6 83.1 * 65.3 81.1 * 65.6 HR (bpm) 76.0 * 59.6 77.5 * 64.4 70.4 * 59.8 AIx 18.2 19.0 19.7 22.7 25.9 * 35.0 AIx75 19.3 * 10.4 20.6 15.7 23.4 26.4 RM 55.2 * 63.2 59.7 * 68.8 62.3 * 71.5 Table:Mean day and night values for peripheral systolic blood pressure (pSBP), peripheral diastolic blood pressure (pDBP), central systolic blood pressure (cSBP), central diastolic blood pressure (cDBP), heart rate (HR), augmentation index (AIx, AIx75) and reflection magnitude (RM) * marks a significant difference between day and night (t-test, p<0.05).