P98 AGE AND GENDER DIFFERENCES IN VARIABILITY OF WAVE REFLECTIONS OVER 24 HOURS: THE INTERNATIONAL 24-HOUR AMBULATORY AORTIC BLOOD PRESSURE CONSORTIUM (I24ABC)

Abstract

Background: Wave reflection parameters predict cardiovascular events, but 24-hour profiles in large samples of healthy adults are unknown. Methods: In 1645 individuals free from antihypertensive drugs from 11 centers in Europe and Asia, 24-hour blood pressure monitoring with a validated oscillometric brachial cuff (Mobilograph, I.E.M., Stolberg; Germany) was performed. Brachial waveforms were acquired and processed with ARCSolver algorithms to derive information relating to wave reflections using pulse waveform analysis (heart-rate corrected augmentation index-AIx75, augmentation pressure-AP) and wave separation analysis (backward wave amplitude-Pb, reflection magnitude-RM). Nighttime/daytime difference (N/D) was nighttime (01.00–06.00) minus daytime (09.00–21.00) values/daytime values. Participants were categorized as young (13–39 years; male/female: 219/112), middle-aged (40–66 years; male/female: 545/553), and old (67–104 years; male/female: 86/130). Results: 24-hour measures of wave reflections increased with increasing age and were significantly lower in men compared to women (AIx75: 18.3 vs 28.0 %, AP: 10.1 vs 14.9 mm Hg, Pb: 18.9 vs 20.0 mm Hg, RM: 63.0 vs 66.2). AIx75 was higher during daytime compared to nighttime (23.3 vs 21.3%), but only in young and middle-aged participants. For all participants, AP (11.6 vs 14.5 mm Hg), Pb (18.5 vs 21.7 mm Hg), and RM (62.9 vs 68.8) were higher during nighttime compared to daytime. N/D varied with age and was more pronounced in younger individuals. Conclusion: 24-hour variability of wave reflection parameters differs according to age and gender. In future, this information could be useful for tailoring individual cardiovascular risk management.