P5.17 NOCTURNAL CHANGES OF AUGMENTATION INDEX MAY BE RELATED TO DIPPING STATUS

Abstract

Aim: Important prognostic significance of day-night brachial blood pressure (BP) decline for cardiovascular morbidity and mortality has been established. It is little known about diurnal variations of arterial stiffness parameters – augmentation index (AI@75) and aortic pulse wave velocity (PWV) as the non-invasive techniques for their 24-h ABPM has been just recently developed and validated. The aim of the study was to evaluate diurnal variations of AI and PWV in hypertensive subjects. Methods: ABPM was done in untreated hypertensive subjects using BPLab VASOTENS (“OOO Petr Telegin”, Nizhniy Novgorod, Russia) brachial oscillometric device which allows to derive aortic AI and PWV. Analysis included the successful ABPM results of 87 (47 male, age 61 years) subjects. Diurnal BP pattern was evaluated by diurnal index of systolic BP=(daytime SBP-nighttime SBP)/day-time SBP. Subjects were classified to dippers, non-dippers, night-peakers and over- dippers using usual cut-offs for brachial systolic BP. Results: In dippers (n=29) nocturnal decline was 12,8±2,5% for brachial and 16,3±3,6% for aortic SBP, night- and day-time values of PWV and AI@75 were similar: 10,8±1,1 and 10,2±1,3 m/s, and 25,9±15,0 and 27,3±14,5%, respectively. In non-dippers nocturnal decline was 5,9±2,6% for brachial and 4,3±2,9 for aortic SBP, day- and night-time PWV values were similar (10,8±0,9 and 10,3±0,9 m/s), AI@75 tended to be higher during night then daytime (32,7±16,8 vs 27,9±14,6%). In night-peakers (n=13) night-time nocturnal decline was −3,9+3,75% for brachial and −4,8±3,9% for aortic SBP, day- and night-time PWV values were similar (10,6±1,0 and 10,5±1,3 m/s) and AI@75 tended to be higher during night then daytime (27,6±16,0 vs 36,8±32,6%). In over-dippers (n=4) night-time nocturnal decline was 20,7±0,9 for brachial and 20,2±1,0 for aortic SBP, day- and night-time PWV values were similar (10,3±0,9 and 9,5±0,8 m/s) and AI@75 tended to be higher during day then night-time (20,2±13,1 vs 14,2±18,7%). Conclusion: The results suggest that PWV is relatively constant during 24-h, but nocturnal changes of AI@75 may vary across different SBP diurnal patterns