[Inter-arm blood pressure difference: Consecutive versus simultaneous measurements in treated and controlled...

The inter-arm difference (IAD) of systolic blood pressure (SBP) is associated with higher cardiovascular risk. We compared simultaneous and consecutive recordings in measuring IAD of SBP, and evaluated reproducibility between visits. 143 hypertensive patients (63.8±9.5 years, 51.7% women) treated and controlled with stable antihypertensive medication for a period of ≥3 months were included. Blood pressure (BP) in both arms was measured simultaneously and consecutively with an automatic oscillometric device, in two visits. The IAD of the simultaneous SBP was significantly lower compared to the consecutive one, both in the first (3.51±4.1 vs. 4.40±3.7mmHg; P<.01) and in the second visit (3.62±3.5 vs. 5.69±5.1mmHg; P<.001). When the IAD of SBP was categorized as ≥10 or <10mmHg, the reproducibility between visits was insignificant in both simultaneous measurements and consecutive measurements. The frequency of initial dominance was similar between the left and right arm in simultaneous ones (46.2 vs. 43.3%), and greater in the right arm in consecutive ones (55.2 vs. 38.5). The persistence of dominance between both visits was significantly higher when SBP was measured simultaneously (54.4% vs. 45.5%; P<.01). Our study shows that to define the arm with the highest BP, simultaneous measurements are preferable. In treated and controlled hypertensive patients, the poor persistence of initial dominance between visits requires us to review the recommendation of recording, during follow-up, the BP in the arm where it was highest on the first visit.