Accurate measurement of blood pressure (BP) is crucial for hypertension management. Accuracy of brachial cuff (BCUFF) devices to measure invasive (intra-arterial) BP at the brachial artery (BINV) and aorta (AINV) has never been systematically assessed. This study aimed to determine the: 1) relationship between BINV and AINV; 2) accuracy of BCUFF devices to estimate invasive BP and; 3) accuracy of BCUFF devices to classify BP thresholds.Design and Method:
Three individual patient meta-analyses (by search of online databases and systematic review supplemented by measurements in a tertiary hospital cardiac catheterization laboratory) were performed to determine: 1) BINV versus AINV BP; 2) BCUFF versus BINV BP and AINV BP and; 3) BCUFF for BP classification versus invasive BP.Results:
Most subjects (90%) were patients undergoing cardiac catheterization (total N = 3004; mean age 58.7 years, 95%CI [54.0, 63.4], 68% male). As shown in the table: 1) BINV systolic BP (SBP) was significantly higher than AINV SBP whilst AINV diastolic BP (DBP) was slightly higher than BINVDBP. 2) BCUFF underestimated BINV SBP and overestimated BINV DBP. The mean difference between BCUFF SBP and AINV SBP was small, whilst BCUFF DBP overestimated AINV DBP. However, according to mean absolute difference, BCUFF and AINV showed poor agreement. 3) BCUFF correctly classified 31.1/28.4% of high-normal (SBP 130–139 mmHg), 54.2/52.6% of grade I (SBP 140–159 mmHg) and 45.2/50.3% of grade II (SBP 160–179 mmHg) hypertension cases, using BINV/AINV, respectively, as the reference. Correct classification was more frequent for SBP BCUFF values < 120 mmHg or ≥180 mmHg (both > 75%).Conclusions:
While recognising the clinical importance of BCUFF devices, there is wide variability in device accuracy for measuring intra-arterial BP. Although BCUFF devices are reasonable for correctly classifying BP at low and very high BP thresholds, more accurate BCUFF devices in the high-normal BP to grade II hypertension range should improve hypertension management.