P6.05 PRESSURE DEPENDENCY OF STIFFNESS DIFFERS WITH AGE: AGREEMENT BETWEEN OBSERVATIONS IN TREATED HYPERTENSIVES AND THE REFERENCE VALUES FOR ARTERIAL STIFFNESS POPULATION

Abstract

Background: Arterial stiffness measures have a known dependency on actual blood pressure, requiring due consideration in risk assessment and treatment monitoring. Given the impact of age on arterial wall structural properties, this pressure-dependency might significantly differ between younger and older patients. Methods and results: Using our previously developed approach combining carotid artery echo-tracking and tonometry waveforms, we obtained individual pressure-area curves in 13 outpatients at baseline (anti-hypertensive medication absent or discontinued) and at 3-month follow-up (medication reinstalled or increased). Using modelled-curve prediction, we found no change in the pressure-area relation after 3 months of treatment; i.e. carotid stiffness (cPWV) changed according to the BP shift along the baseline curve (measured=modelled cPWV; Table A). We discriminated patients aged under and over 50 yrs and averaged the respective groups’ pressure-area curves using an established single-exponential model to estimate arterial stiffness for typical hypertensive (160/90) and normotensive (130/70) blood pressure ranges for both age groups (mean ages 40 and 65 yrs; Table B). We compared these values with the aortic stiffness values found in the Reference Values for Arterial Stiffness Collaborative study (2010 data) for corresponding mean arterial pressures (i.e. 118 and 94 mmHg) and mean ages (Table C). Conclusion: Within patients, short-term changes in arterial stiffness of ∼1 m/s in the presence of >10 mmHg BP lowering can be deemed entirely pressure dependent. This pressure dependency of arterial stiffness increases with age, in part explaining the well-established pattern between stiffness, BP and age at (reference) population level.