Simultaneous measurements of blood pressures in right and left brachial arteries

The most recent guidelines do not mention which arm to use to measure blood pressure or interarm blood pressure differences. In 357 women and 171 men, mean age 79 +/- 10 years, 2 geriatricians simultaneously measured brachial artery blood pressure (BABP) with the patient in the sitting position. All blood pressure measurements were performed using the same 2 machines, which were calibrated and marked 1 and 2. The machines and cuffs were transferred to the opposite arm for a repeat measurement in all patients and the results of the 2 blood pressures averaged. Patients with conditions that may cause a disparity in blood pressure between the right and left arms were not included in this study. The right systolic BABP was >/= 10 mm Hg higher than the left systolic BABP in 35 of 528 patients (7%), and the left systolic BABP was >/= 10 mm Hg higher than the right systolic BABP in 35 of 528 patients (7%) (P = not significant). The right diastolic BABP was >/= 10 mm Hg higher than the left diastolic BABP in 16 of 528 patients (3%), and the left diastolic BABP was >/= 10 mm Hg higher than the right diastolic BABP in 12 of 528 patients (2%) (P = not significant). There was no significant difference in prevalence of hypertension, atherosclerotic vascular disease, diabetes mellitus, or hypercholesterolemia in patients with or without a >/= 10-mm Hg difference in right and left systolic BABP and in right and left diastolic BABP. Interarm differences of >/=10 mm Hg in systolic BABP were found in 14% of elderly patients and of >/= 10 mm Hg in diastolic BABP in 5% of elderly patients. The higher blood pressure should be used for the diagnosis of hypertension, and the blood pressure in that arm used for all follow-up blood pressure-evaluating therapy.