How Accurate is Cuff-Measured Blood Pressure?

The accuracy of cuff-measured blood pressure (BP) is inconsistent for both brachial and aortic intra-arterial BP, adversely influencing the correct BP classification, according to an analysis published July 24 in the Journal of the American College of Cardiology.

Using data from studies conducted between the 1950s to 2016, Dean S. Picone, BMedRes(Hons) et al., conducted three individual participant data meta-analyses that evaluated intra-arterial aortic BP, intra-arterial brachial BP and cuff BP. A total of 74 studies with 3,073 participants were included. Across the three meta-analyses, patients were generally middle-to-older age, predominately male and overweight.

The results of the analyses showed intra-arterial brachial systolic blood pressure (SBP) was higher than aortic values (8.0 mm Hg; p < 0.0001) and intra-arterial brachial diastolic BP (DBP) was lower than aortic values (1.0 mm Hg; p = 0.038).

Cuff BP significantly underestimated intra-arterial brachial SBP (5.7 mm Hg; p < 0.0001) but overestimated intra-arterial DBP (5.5 mm Hg; p < 0.0001). Cuff and intra-arterial aortic SBP showed a small mean difference (0.3 mm Hg; p = 0.77) but poor agreement (mean absolute difference 8.0 mm Hg).

The study authors write that the most important finding was the inaccuracy of cuff BP when compared with intra-arterial brachial BP and aortic BP because these deviations substantially influenced BP classification using clinical guideline criteria. They also highlight the wide interdevice variability for measuring SBP, DBP and pulse pressure.

In an accompanying editorial, George S. Stergiou, MD, PhD, et al., note that "despite the remaining important methodological issues in arterial BP measurement, which were nicely demonstrated in the analyses by Picone et al., hypertension management in clinical practice has been a great success story in medicine." They add, "Whether the more accurate measurement of brachial BP or the implementation of accurate aortic (central) BP measurement in clinical practice can contribute to more efficient prevention of cardiovascular disease are challenging research questions. To allow these questions to be addressed, novel noninvasive technologies that provide such measurements in static and dynamic conditions need to be developed and properly validated. These are the 21st century questions on BP measurement methodology that the scientific community should put on its research agenda."


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