INTER-ARM BLOOD PRESSURE DIFFERENCE

Abstract

Objective: An increased inter-arm systolic blood pressure difference (IBPD) is an easily determined physical examination finding and a significant IBPD has recently been associated with worse cardiovascular outcome. But the prevalence of IBPD in Asian population is unknown and the relationship between IBPD and blood pressure (BP) variability is not yet determined. This study was performed to describe the prevalence and clinical characteristics of the patients with increased IBPD and to examine the association between IBPD and BP variability.Design and method: A representative population (aged 20–65 years) was selected by list-assisted random-digit dialing method from a city with a population of one million. The BP of two arms was simultaneously measured using validated automatic BP measurement devices for 3 times and ambulatory blood pressure monitoring (ABPM) was performed in all included subjects. An increased IBPD was defined as > 10mmHg using the average of 3 BP differences obtained simultaneously in both arms. Results: Five hundreds of subjects were included in this study, and 13 subjects were excluded because of inadequate ABPM measurements. Mean age was 46.9 ± 9.4 years and 309 participants were female (63.4%). Overall systolic BP and diastolic BP were 118.5 ± 13.4 mmHg and 75.1 ± 10.3 mmHg and mean systolic IBPD was 5.7 ± 4.0mmHg. Of 487 subjects, 66 subjects (13.6%) had an increased systolic IBPD. Compared with those with normal IBPD, subjects with increased systolic IBPD showed higher clinic BP (127.2 ± 13.7 vs. 117.2 ± 12.8 mmHg in systolic BP, P < 0.001; 78.7 ± 11.2 vs. 74.6 ± 10.1 mmHg in diastolic BP, P = 0.002), higher 24-hour systolic BP (118.5 ± 12.0 vs. 115.6 ± 10.8 mmHg, P = 0.045) and higher 24-hour pulse pressure (42.4 ± 7.4 vs. 40.2 ± 6.5 mmHg, P = 0.012). The subjects with increased systolic IBPD showed higher 24-hour BP variability; increased standard deviation of daytime BPs, increased weighted standard deviation of BPs, increased coefficient of variation of daytime BPs and increased average real variability of both 24-hour BPs and daytime BPs (Table). There was no significant difference in nighttime dipping pattern of increased IBPD subjects. Conclusions: In this community-based cohort, an increased IBPD is common and associated with an increased short-term BP variability. Bilateral BP measurements should be emphasized in routine clinical practice.