Is the blood pressure of right arm measured with synchronous four-limb method is equal to that with single arm method?

Objective: Synchronous four-limb blood pressure (BP) measurement (four-limb method) is widely used for diagnosing peripheral artery diseases in clinical practise, but it is unclear whether the BP of right arm measured with this method is similar to that measured with single arm method.

Methods: This study included 198 in-patients (aged 18-89, mean age 60.1± 13.9 years old, 109 males). They were divided into four groups on the therapy as renin-angiotensin system inhibitor (46 patients), calcium channel blocker (43 patients), beta receptor blocker (27 patients), and combination (Com, 82 patients) groups. The patients were randomly instructed to follow one of two BP measurement proposals designed to avoid the bias induced by BP measurement order. The result with single arm method was recorded as RA-1 and that with four-limb method as RA-4. The difference between RA-4 and RA-1 was calculated as Dif-RA. The percentage increase (PI) was also calculated on the formula: (RA-4 - RA-1)/RA-1.

Results: The mean Dif-RA on SBP and DBP were 1.9/1.5 mmHg. Although the levels of SBP, DBP and pulse pressure of RA-1 were different, the PI of these parameters were comparable among four treatment groups. Multivariate regression analyses showed that age and SBP of RA-1 were positive independent factors for Dif-RA on SBP.

Conclusion: The SBP and DBP of right arm measured with synchronous four-limb method are 1.9/1.5 mmHg higher against the single arm method in treated hypertensives, and the increase extent of BP is not associated with the used drugs.