P3.02 MORNING BLOOD PRESSURE SURGE, BLOOD PRESSURE VARIABILITY AND AORTIC STIFFNESS IN ESSENTIAL HYPERTENSION

Abstract

Morning blood pressure surge is associated with increased cardiovascular risk, possibly due to its ability to reflect short-term BP variability and/or its link with arterial stiffness. The link between morning BP surge and vascular stiffness is not defined. 689 untreated hypertensives (48±10 years, BP 149/92±17/10 mmHg) underwent c-f PWV and 24-h ambulatory BP measurement. Morning surge was calculated as: sleep-trough surge (STS, 2-hour average SBP after wake-up minus average of 3 SBP centered on the lowest nighttime reading), pre-awakening surge (PAS, 2-hour average SBP after wake-up minus 2-hour average SBP before wake-up), and rising BP surge (RBS, SBP on rising minus the lowest SBP in the 30’before). Average real variability (ARV, 24h average of the absolute differences between consecutive SBP), was considered a measure of short-term SBP variability. STS and RBS were directly correlated to cfPWV (r=0.17 and r=0.12,p<0.01) and ARV (r=0.28 and r=0.23,p<0.001), while PAS had no such relationships. Patients in the top quartile of STS (>39 mmHg) had higher age- and 24-h mean BP-adjusted cfPWV (9.73±2 vs 9.29±2 m/s, p=0.004), while no difference was found for the top quartile of PAS or RBS. In a multivariate regression, high STS values predicted a high cfPWV (β=0.08,p=0.038), independently of age, sex, 24-h mean BP and nocturnal BP reduction. After adding ARV (β=0.17,p<0.001) to the model, the relationship between STS and cfPWV was no longer significant (β=0.05,p=0.17). Morning SBP surge, calculated as STS, has a positive relation with aortic stiffness in hypertension, which is no longer significant after adjusting for 24-h short-term BP variability.