Abstract P392: Association Between Blood Pressure Variability and Subclinical Measures of Cardiovascular Disease in Desk Workers

Abstract

Introduction: Previous research has demonstrated that variability in resting blood pressure (BP) across arms, measurements, or days may be associated with an increased risk for cardiovascular disease (CVD) and mortality. Yet, the extent to which BP variability increases cardiovascular risk and the mechanisms explaining this association are unclear. This study evaluated associations between BP variability with subclinical pathways of CVD development (arterial stiffness (pulse wave velocity [PWV]) and cardiac autonomic function (heart rate variability [HRV]) in desk workers. Hypothesis: Higher BP variability will be associated with higher PWV and lower (worse) HRV Methods: This secondary analysis of baseline data from the Effect of Reducing Sedentary on Blood Pressure randomized controlled trial included 265 sedentary and inactive desk workers (mean age 44.9±11.6 years; 82.0% white; 57.9% female) with elevated-to-stage 2 hypertension and who were not using antihypertensive medication. Sequential BP measurements determined the arm with the higher systolic BP by using an oscillometric device (Omron HEM-907XL). BP was then measured at least twice from the arm with the higher systolic BP at the first (visit-1) and second (visit-2) visits, occurring ≤30 days apart. Systolic BP variability metrics included inter-arm (first measurements between arms at visit-1), intra-arm (first two measurements on the arm with higher systolic BP at visit-1), and inter-visit (average BP from repeated measurements on the same arm across visits-1 and -2). Subclinical measures of CVD included resting carotid- femoral(cfPWV) and carotid-radial(crPWV) PWV (Complier Analyse) and the log transformed standard deviation of normal R-R intervals (SDNN) and the root mean square of the successive differences (RMSSD) HRV measures (Polar Electro). Adjusted linear regression estimated the associations between subclinical measures of CVD and BP variability metrics; Metrics were operationalized into three categories: differences of 0-5 mmHg, 6-10 mmHg, and 11 or more mmHg. Results: The prevalence of having 6 mmHg or more difference for the inter-arm, intra-arm, and inter-visit systolic BP was 43%, 38%, and 53%, respectively. PWV and HRV were not different across categories of inter-arm systolic BP variability or inter-visit systolic BP variability (all p>0.05). However, a same-day intra-arm difference in systolic BP of 6-10 mmHg within visit-1 was associated with higher cfPWV (β=0.42 m/s, (95% CI: 0.07, 0.77) as compared to those with an intra-arm difference of 0-5 mmHg. Conclusion: These data suggest that higher systolic BP variability in the same arm within visit, but not variability across arms or between visits, may be associated with higher aortic stiffness in desk workers with untreated elevated-to-stage 2 hypertension.