Abstract P385: Arterial Stiffness and Contralateral Differences in Ankle Blood Pressure: The Atherosclerosis Risk in Communities (ARIC) Study

Abstract

Background: A large inter-arm difference in brachial systolic blood pressure (SBP) (>10 or 15 mmHg) is strongly associated with elevated cardiovascular mortality. It is currently not known whether such contralateral differences in SBP occur in ankle blood pressure. Although contralateral differences in SBP have been attributed to peripheral vascular disease, physiologic factors such as arterial stiffness could also be at play. Accordingly, the aims of this study were to assess the prevalence of brachial and ankle contralateral SBP differences in a sample of community dwelling older adults, and to determine whether this difference is associated with arterial stiffness. Methods: A total of 2,413 adults (39% male, mean age of 75 years) from the ARIC study with proper consent and non-missing outcomes were included, after excluding 968 subjects with arrhythmias (N=763), BMI >40 kg/m 2 (N=165), and missing covariates (N=40). The automatic vascular screening device was used to measure blood pressure simultaneously in the arms and ankles and to measure arterial stiffness by pulse wave velocity (PWV). PWV was assessed between the heart and ankle (haPWV), femoral artery and ankle (faPWV), and brachial artery and ankle (baPWV) in the right and left sides. The measurements were performed twice, and the results of the 2 readings were averaged. Multivariable logistic regression was used to examine characteristics associated with contralateral differences ≥15 mmHg in brachial and ≥12 mmHg in ankle SBP. Results: The mean±SD absolute contralateral differences in brachial and ankle SBP were 0.25±4.95 and 0.17±10.12 mmHg. Prevalences of inter-brachial SBP differences >10 and >15 mmHg were 6.4% and 0.9% respectively; the corresponding prevalences for inter-ankle SBP were 25.6% and 11.7%. Height, body weight, ankle brachial index (ABI), and level of SBP were associated with larger inter-brachial SBP differences. Age, body weight, ABI, and contralateral differences in haPWV, faPWV, and baPWV were related to inter-ankle SBP differences. Inter-ankle SBP differences were associated with contralateral differences of ≥100 cm/s in haPWV (OR=2.9 [95% CI=1.9-4.4]), ≥200 cm/sec in faPWV (OR=2.1 [95% CI=1.3-3.3]), and ≥250 cm/sec in baPWV (OR=2.8 [95% CI= 1.9-4.0]). The associations remained nominally significant after adjustment for age, gender, height, body weight, current smoking, SBP, and ABI. Conclusions: Inter-ankle differences in SBP of 10 mmHg or greater and 15 mmHg or greater are common in older adults, namely 25% and 12%, respectively. The magnitude of inter-ankle, but not inter-brachial, differences in SBP in older adults is associated with measures of local/regional vascular elasticity.