S-46-2: DAYTIME MAXIMUM AMBULATORY BLOOD PRESSURE AND RISK OF STROKE IN INDIVIDUALS WITH INCREASED AMBULATORY ARTERIAL STIFFNESS INDEX: THE JAMP STUDY

Abstract

Objective: The hypothesis of this study is that maximum ambulatory BP during daytime is a risk of cardiovascular events. We further hypothesize that this association may be remarkable in the population with increased arterial stiffness, because BP variability is linked to increased arterial stiffness. Methods: A total of 6294 Japan Ambulatory Blood Pressure Monitoring Prospective study participants (mean age, 68.6 ± 11.7 years; 78% treated hypertensive patients) with at least 1 cardiovascular risk factors performing ambulatory BP monitoring were followed for 4.5 years. Daytime maximum BP was calculated as the highest 1 hour moving average of 2 consecutive systolic BP readings during daytime defined by referring to the diary. Ambulatory arterial stiffness index (AASI) was calculated as 1 minus the regression of diastolic BP plotted against systolic BP obtained from individual 24-hour BP. Results: During a follow-up, there were 217 atherosclerotic cardiovascular events (119 stroke, 98 coronary artery disease). Divided into quartiles of daytime maximum BP, the top quartile (≧179.4 mmHg) was a risk of stroke events compared to other quartiles after adjustment for covariates (Hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.02–2.27), but not a risk of coronary artery disease. In the higher AASI group (≧0.5783), this association was observed (HR, 1.89; 95%CI, 1.13–3.15) but not in the lower ASSI group. The highest risk of stroke among BP groups was observed the individuals with 24-hour systolic BP of at least 130 mmHg and the top quartile of daytime maximum BP with a HR (95%CI) of 2.44 (1.27–4.68), compared with those with 24-hour systolic BP of less than 130 mmHg and other quartiles of daytime maximum BP in the higher AASI group, but this association was not found in the lower AASI group. Conclusion: Maximum ambulatory BP during daytime was a risk of cardiovascular events, especially in increases arterial stiffness represented as AASI.